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VOL. LVII.

MICROBES, FERMENTS

A.ND

MOULDS

E. L. TEOUBSSAKT

WITH ONE HUNDRED AND SEVEN ILLUSTRATIONS

LONDON
KEGAN PAUL, TRENCH & CO., 1, PATERNOSTER SQUARE

1886

LIx

UNIVERSITY OF CALIFOR1KS
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( Tfte rights of translation and of reproduction are reset vcd )

PREFACE.

THE number of works which treat of microbes is
already considerable, but they have all been written
for a special public of physicians or naturalists, and
imply that the reader is familiar with the ideas
already established on pathology or on cryptogamic
botany.

Although the science of microbes is of recent
origin, it has made immense progress in the course of
a few years. It is, moreover, essentially a French
science, since it is owing to Pasteur's admirable
labours, as well as to his solid genius, aided by the
faith and energy of his disciples, that this science
has been able to overcome the prejudices of ages, and
to penetrate into the very heart of the ancient theory
of medicine, so as to transform and regenerate it.

Every one now speaks of microbes, yet few of those
who make use of the term have any clear conception

vi PKEFACE.

of the beings in question, or could give an exact
account of the function which microbes fulfil in
nature. And yet this function concerns us all.

The man of the world ^who desires to take part in
a scientific discussion; the lawyer who has to treat of
a question of hygiene in the presence of experts; the
engineer, the architect, the manufacturer, the agricul-
turist, the administrator — all have to consider such
questions, and they will find in this work clear and
precise notions on microbes, notions which they would
find it difficult to glean from books designed for
physicians and professional botanists.

The questions of practical hygiene, those which
concern domestic economy, agriculture, and manufac-
tures, and which are connected with the study of
microbes, must especially demand attention. These
are pertinent questions in such a book as this. There
is a certain danger in vulgarizing notions of medicine,
strictly so called; but it can only be beneficial to
make every one acquainted with the precepts of hy-
giene, which cannot become popular until they have
penetrated into the habits and routine of national
life.

There is much to be done before modern society
is practically on a level with the achievements of
science; many prejudices must be uprooted, and many

PREFACE. Vll

false notions must be replaced by those which are
sounder and more j ust.

For this reason, we have endeavoured to make
this work intelligible to all. It may be read with
profit by those who possess the elementary notions
of natural science which are included in the course
of primary instruction. We therefore hope that the
volume may find a place in the libraries of secondary
instruction, and in public libraries.

Although the work is not specially intended for
physicians, yet practical men may not be indisposed
to glance at it : it may, at any rate, serve as an intro-
duction to the much more learned works of Cornil
and Babes, of Duclaux, Klein, Koch, Sternberg, etc.
We have given an important place to the botanical
question, which is too often neglected in works on
microbian pathology. From this point of view, the
narrow bond which connects bacteria with ferments
and moulds has to some extent marked out the plan
we have adopted ; namely, that of passing from the
known to the unknown, from what is visible with the
naked eye to that which is only visible with the aid
of the microscope.

ANGERS, September 10, 1885.

TABLE OF CONTENTS.

INTRODUCTION.

PACK

MICROBES AND PROTISTA . ... 1

CHAPTER I.

PARASITIC FUNGI AND MOULDS ... ... ... ... 9

I. General remarks on fungi ... ... ... 9

II. Basicliomycetes : uredinese, the rust of wheat and grasses 14

III. Ascomycetes : ergot of rye ; mould of leather and dried fruit 20

IV. Oomycetes, mucorinese, or moulds, strictly so called ; pero-

uosporse; potato-fungus ... ... ... 27

V. Parasitic fungi of the vine: o'idium, mildew, etc. ... 32

VI. Habitat and station of parasitic fungi: their destructive

action ... ... ... *.. ... 43

VII. Parabitic fungi of insects, considered as auxiliaries to man 47

VI 1 1. Muscardin, or disease of silkworms ... ... ... 50

IX. Parasitic fungi of the skin and mucous membrane of man

aud other animals ... ... ... ... 51

CHAPTER II.

NTS AND ARTIFICIAL FERMENTATIONS ... ... 6G

I. Definition of fermentation... ... ... ... 66

II. Vegetable nature of ferments, or yeasts ... ... ... 72

III. Ferments of wine ; alcoholic fermentation ... ... 74

IV. Beer-yeast ... ... ... ... ... ... 78

V. Concerning some other fermented drinks ... ... 82

VI. Yeast of bread 84

X CONTENTS.

CHAPTER III.

MICROBES, STRICTLY so CALLED, OR BACTERIA

I. The vegetable nature of microbes
II. Classification of microbes, or bacteria ...

III. The microbe of vinegar, and acetic fermentation

IV. The microbes which produce the diseases of wine
V. The microbe of lactic fermentation

VI. The ammoniacal fermentation of urine
VII. Butyric fermentation of butter, cheese, and milk
VIII. Putrid fermentation : game-Havour
IX. Aerobic and anaerobic microbes ...
X. The microbes of sulphurous waters
XT. The microbes which produce saltpetre
XII. The microbes which destroy buildiug materials

XIII. The microbes of chalk and coal ...

XIV. Chrcmogeriic microbes
XV. The microbe of baldness

CHAPTER IV.

THE MICROBES OF THE DISEASES OF DOMESTIC ANIMALS
I. Anthrax, or splenic fever
II. Vaccination for anthrax

III. Fowl cholera ... ...

IV. Swine fever

V. Some other diseases peculiar to domestic animals

VI. Rabies

VII. Glanders ...

VIII. Pebrine and flacheiie, two diseases of silkworms

CHAPTER V.

THE MICROBES OF HUMAN DISEASES ... ...

I. Microbes of the air, the soil, and water ...
II. Microbes of the mouth and digestive canal in a healthy
man

III. The virulent microbe of human saliva

IV. The microbes of dental caries

V. The microbes of intermittent or marsh fevers ...

VI. The microbes of recurrent fever and yellow fuver

CONTENTS. XI

PAGE

VII. Typhoid fever and typhus ... ... ... 191

VIII. The microbe of cholera ... ... 195

IX. Eruptive fevers : scarlatina, small-pox, measles, etc. 209

X. The microbes of croup and whooping-cough ... ... 215

XL The microbes of phthisis and leprosy ... ... 223

XII. The microbe of pneumonia ... ... ... ... 229

XIII. Some other diseases due to microbes ... ... 230

XIV. The microbe of erysipelas ... ... ... ... 232

XV. The microbes of pus, septicemia, etc. ... ... 234

XVI. The microbes of other diseases, due to wounds ... 236

X.V1I. The mode of action of pathogenic microbes : ptomaines 237

CHAPTER VI.

PROTECTION AGAINST MICROBES ... ... ... ... 242

I. Antiseptic treatment of wounds : Guerin's protective treat-

' ment ; Lister's dressing ... ... ... ... 242

II. Hygiene of drinking - water : water free from microbes ;

Chamberland filter 245

CHAPTER VI I.

LABORATORY RESEARCH, AND CULTURE OP MICROBES ,,. 258

CHAPTER VIII.

POLYMORPHISM OF MICROBES ... ... ... ... 272

CHAPTER IX.

: rsiON ... ... ... ... ... ... 285

The Microbian Theory compared with other Theories set forth to

explain the Origin of Contagious Diseases ... ... 285

APPENDIX.

A. Terminology of Microbes ... ... ... ... 301

B. Micrococcus of phosphorescence ... ... ... 304

C. Diseases of plants caused by bacteria ... ... ... 305

D. Ptomaine of the microbe of fowl cholera ... ... 306

K. Cesspools. System of conveying everything to the sewer's 306

F. Sewers of Paris and the Plain of G-ennevilliers ... 307

G. Useful microbes ... ... ... ... ,.. 303

II. Ptomaines of fish ... ... ... ... 308

, 309

MICROBES, FERMENTS, AND MOULDS.

INTRODUCTION.

MICROBES AND PROTISTA.

MICROBES are the most minute living things which
the microscope permits us to see distinctly, so as to
study their organization. They are for the most part
invisible to the naked eye, and even by the aid of a
simple lens. In order to form an exact idea of their
forms and structure, we require the strongest magni-
fiers of modern instruments, which enlarge the object
500, 1000, and even 1500 diameters.

The word microbe has been recently introduced
into the French language ; it did not exist eight years
ago, and for this reason it will be sought for in vain
in most dictionaries. It was under the following cir-
cumstances that this term, now in such general use,
was invented by Se"dillot, an eminent surgeon, whose
recent death is deplored by France.

Those naturalists who have studied the most

2 MICROBES, FERMENTS, AND MOULDS.

minute living things have at all times been at a loss
to decide whether they have had to do with animals
or plants. There can be no such doubt when we com-
pare a tree of which the roots are fastened in the soil
with a quadruped which moves freely on its surface.
But these are highly developed forms, the one in the
vegetable, the other in the animal kingdom. The
lower representatives of the two kingdoms are, on
the other hand, often so much alike as to baffle the
most experienced naturalist. The animals which are
assigned to the order of Zoophyta, or animal -plants,
have, as the name indicates, a form which led them to
be for a long while regarded as plants ; many of them
are fastened to the bottom of the sea or to rocks as if
by actual roots, and, when superficially examined, their
movements do not differ much from those which may
be produced in true plants, as, for instance, in the
mimosa.

Many of the lower plants, belonging to the groups
of Algae and Fungi, live in the water without being
fixed by roots ; many are animated by more or less
apparent motion, at any rate during part of their
existence, so that it is often somewhat difficult to dis-
tinguish them under the microscope from those beings
which are generally called Infusoria, and which are
true animals.

Hence it follows that the boundary between the
animal and vegetable kingdoms remains indefinite,
and that many of those microscopic organisms which

MICROBES AND PROTISTA. 3

we have now to consider, may be assigned indifferently
to one or the other kingdom.

Bory de Saint-Vincent, a naturalist belonging to
the early part of the century, and after him Hseckel,
have attempted to evade this difficulty by creating
between the animal and vegetable kingdoms an inter-
mediate kingdom, which they have named Protista,
indicating thereby that it includes the first animals
which in the geological ages appeared on the earth's
surface. This kingdom of Protista includes the fol-
lowing groups, starting from the simplest and going
on to those which are more complex : —

*1. Monera (or Microbes, strictly so called ; Schizomycetes, Bac-
teria, Vibrioncs, etc.)-

2. Amorphous Rhizopoda (or Amoebse).

3. GregarinidsB.

4. Flagellata.

5. Catallacta.

6. Infusoria.

7. Acinetse.

8. Labyrinthulae.

9. Diatomacese.
*10. Myxomycetes.
*11. Fungi.

12. Thalamophora (Foraminifera or Rhizopoda with a calcareous

skeleton).

13. Radiolaria (or Rhizopoda with a silicious skeleton).

The groups marked with an asterisk are those
which we propose to study in this work. For the
most part, the organisms assigned to them resemble
plants in their general characters. They are parasites
which derive their nutriment from other living beings.

For this reason, many of these organisms are the

4 MICKOBES, FERMENTS, AND MOULDS.

cause of the more or less serious diseases which affect
animals or plants. Naturalists who regard these para-
sites as animals have termed them Microzoaria (from
two Greek words signifying small animals). Those
who regard them as plants have called them Micro-
phyta (small plants), and it is still disputed which
term is the most applicable to them. In other words,
it is still undecided whether they should be classed in
the animal or vegetable kingdom.

It was at the Paris Academy of the Sciences, on
the llth of March, 1878, that Sedillot took part in one
of the probably interminable discussions between the
advocates of the Microzoaria and those of the Micro-
phyta, and he suggested, with the critical sense for
which he was distinguished, the word microbe, to
which it appeared to him that every one could give
their assent.

In fact, the word microbe, which only signifies a
small living being, decides nothing as to the animal
or vegetable nature of the beings in question.* It has
been adopted by Pasteur, and approved by Littre,
whose competence to decide on neologisms is generally
admitted ; it has been in common use in France for
the last four or five years, and may now be regarded
as definitively adopted into the French language.

This word has not yet been fully introduced into

* Bechamp terms microbes microzyma, or small ferments, since the
chemical reactions which result from their vital activity are generally
fermentations.

MICROBES AND PROTISTA. 5

the English and German languages. In order to in-
dicate the organisms which produce diseases, they
make use of the word Bacteria, which is only the
name of one of the peculiar species assigned to this
group, and the one with which we have been longest
acquainted. In this case, the name is generalized and
applied to an entire group.

The Italian authors who have been recently occu-
pied with the study of microbes have on their part
adopted the name Protista, proposed by Hseckel, and
of which the sense, although not the etymology, is
almost the same as that of the word microbe.

In reply to the question whether there is any real
advantage in establishing an intermediate kingdom
of Protista between the two organic kingdoms of
animals and plants, we must answer in the negative.
This third organic kingdom only serves to render
the structure of our modern classification more com-
plex ; and it includes, as may be seen from the list
given above, a collection of very heterogeneous groups,
which it would be more simple to leave in one or the
other kingdom. We should, in our opinion, approxi-
mate more closely to Nature's plan by only admitting
two great kingdoms : the organic kingdom, which
includes plants and animals ; and the inorganic king-
dom of minerals. The organic kingdom should then
be divided into two sub-kingdoms, animals and
plants, of which microbes or protista, or whatever
else they may be called, should form the connecting

6 MICROBES, FEKMENTS, AND MOULDS.

link, and testify to the common origin of the two
great organic kingdoms.

However this may be, we shall make use of the
word " microbe" as the general designation of all
the minute organized beings which are found on the
borderland between animals and plants. We shall
presently show that in the majority of cases these
beings may be regarded as true plants, and this is at
present generally admitted by most naturalists.

Part played by Microbes in Nature. — The part
played by microbes in nature is an important one.
We find them everywhere ; every species of plant has
its special parasites, and this is also the case with our
cultivated plants — with the vine, for example, which is
attacked by more than a hundred different kinds.
These microscopic fungi have their use in the general
economy of nature ; they are nourished at the expense
of organic substances when in a state of putrefac-
tion, and reduce their complex constituents into those
which are simpler — into the soluble mineral substances
which return to the soil from which the plants are
derived, and thus serve afresh for the nourishment of
similar plants. In this way they clear the surface of
the earth from dead bodies and faecal matter ; from all
the dead and useless substances which are the refuse
of life, and thus they unite animals and plants in an
endless chain. All our fermented liquors, wine, beer,
vinegar, etc., are artificially produced by the species
of microbes called ferments; they also cause bread

MICROBES AND PROTISTA. 7

to rise, and from this point of view they are pro-
fitable in industry and commerce.

But in addition to these useful microbes, there are
others which are injurious to us, while they fulfil
the physiological destiny marked out for them by
nature. Such are the microbes which produce dis-
eases in wine ; most of the changes in alimentary and
industrial substances ; and, finally, a large number of
the diseases to which men and domestic animals are
subject. The germs of these diseases, which are only
the spores or seeds of these microbes, float in the air
we breathe and in the water we drink, and thus
penetrate into the interior of our bodies.

Hence we see the importance of becoming acquainted
with these microbes. Their study concerns the agri-
culturist, the manufacturer, the physician, the pro-
fessor of hygiene, and, indeed, we may say that it
concerns all, whatever our profession or social position
may be, since there is not a single day, nor a single
instant, of our lives in which we cannot be said
to come in contact with microbes. They are, in
fact, the invisible agents of life and death, and this
will appear more plainly from the special study we
are about to make of the more important among
them.

Since it is easier to know and observe beings which
are visible to the naked eye, we shall first speak of
fungi — that is, of the larger microbes, with whose
habits and organization we are also best acquainted.

8 MICROBES, FERMENTS, AND MOULDS.

We will then go on to the study of the more minute
ferments ; and finally to that of bacteria (Schizophyta
or Schizomycetes), which are, strictly speaking, mi-
crobes, and which only become visible with the aid of
the microscope.

CHAPTER I

PARASITIC FUNGI AND MOULDS.

I. GENERAL REMARKS ON FUNGI.

EVERY one is acquainted with the field and forced
mushrooms, two varieties of one and the same species,
wild or cultivated, and often seen at table. It is less
generally known that the truffle is also a fungus:
and that the large class of fungi includes moulds and
many parasites which are more or less microscopic,
which live at the expense of wild and cultivated
plants, and attack animals and also the human subject.
Fungi are among the lower plants, and differ from
higher orders in their mode of life. It is well known
that the large majority of plants are not nourished only
by absorbing the mineral salts which, in a state of
solution, their roots derive from the soil, but also, and
chiefly, by decomposing the carbonic acid of the air,
assimilating the carbon which, as cellulose, enters
into the composition of all their tissues, and giving
forth pure oxygen to the air.

10 MICKOBES, FERMENTS, AND MOULDS.

This function is not, as it was formerly erroneously
supposed, a respiration in the inverse form from that
of animals. All plants without exception breathe
like animals by absorbing oxygen. The assimilation
of carbon is a true nutrition, and as the decomposition
of the carbonic acid gas which results from this assi-
milation sets free a much larger quantity of oxygen
than the plant requires for itself, it was for a long
while believed that- plants really breathed the car-
bonic acid gas of the air, in the inverse method to
that of animals.

Fig. 1. — Agaricas in different stages of development : 2, 3, 3 vertical section showing
the formation of the head. The hyphse «f the mycelium are shown in the lower
part of the figure.

The assimilation of carbon is effected by the leaves
and green parts of plants ; the green, granular sub-
stance termed chlorophyll, which solely gives them
this colour, as may be shown by the microscope, and
which alone subserves this function of nutrition.
Fungi, however, have no leaves nor other green parts ;
that is, they have no chlorophyl. They derive the
cellulose which they contain, as well as all the sub-
stances by which they are nourished, either from

PARASITIC FUNGI AND MOULDS. 11

other plants, or from animals and from the organic
substances which are decomposing in the soil, such
as dung and dead bodies. So that it may be said
of fungi, that they subsist like animals by devouring
plants or other animals ; not like higher plants, which
derive their nutriment from the soil or the air, and
owe nothing to other living beings.

It is for this reason that some naturalists have
regarded fungi as animals, and have classed them in
the animal kingdom. We have seen that Hseckel
and the naturalists of his school have assigned them
to the kingdom of Protista. But setting aside their
mode of nutrition, which is likewise found in plants of
a higher organization, such as the Orobranchece and
some of the Orchidacece, fungi really exhibit all the
characters of plants, and as such we shall here con-
sider them, although they are plants of a peculiar
and very low type.

The class of fungi may be defined by saying that
they are plants devoid of stems, leaves, and roots ; that
they consist only of cells in juxtaposition, devoid of
chlorophyl. They never bear a true flower, and are
simply reproduced by means of very minute bodies,
generally formed of a single cell, which is called a
spore, and which represents the seed.

In fungi of the highest type, such as that commonly
known as the edible mushroom, the part which we
eat and call the umbrella represents the flower or
floral peduncle of other plants, and is in reality only

MICEOBES, FEKMENTS, AND MOULDS.

the support or covering of the spores, which are fixed
on the radiating lamellse that may be seen on in-
verting the umbrella (Figs. 2 and 3). This umbrella
or floral peduncle is the only part of the plant which
appears above the soil, or the organic substances on
which the fungus grows.

But the really essential part of the plant is that

Fig. 2. — Section of one of the lamellae
of the umbrella of Agaricus c:
a, b, spores of the hymenium
(slightly magnified).

Fig. 3. — Spores of the hymenium, greatly
magnified, and resting on their supports
or basides, a.

which does not appear on the surface; namely, the
white filaments or hyphce which creep along the soil,
the manure, or whatever supplies the nutritive matter,
and which represent at once the root, the stem, and the
branches of the plant ; this part is termed the mycelium.
We shall presently see that many of the lower fungi
are without the organ we have called the umbrella, and
which botanists term the hymenium or organ of repro-
duction, and consequently consist only of mycelium.

PARASITIC FUNGI AND MOULDS.

In this case, the spores or seeds are developed in the
cells of the mycelium itself.

This latter mode of reproduction also occurs in the
higher fungi, which therefore possess two modes of
reproduction and two kinds of spores : exogenous
spores, which are externally developed, as we see on
the hymeniurn (Fig. 2); and endogenous or internal
spores, which are developed in
the mycelium (Fig. 4). These
spores not only differ in the
site of their origin, but also in
their form, size, structure, and
in the end they fulfil in the
reproduction of the fungus.
There are in many cases several
forms of exogenous spores.

Classification of Fungi. —
The nature of the spores, and
the very varied mode of reproduction, have led to
the classification of fungi in a certain number of
groups, of which we need only cite the most im-
portant, and those which chiefly concern our present
point of view. Such are —

1. The Hymenomycetes.

2. The Basidiomycetes.

3. The Ascomycetes.

4. The Oomycetes.

Each of these groups is subdivided into several
sections or families. Ferments and Schizomycetes, or

Fig. 4. — Endogenous spores from
the mycelium of Agaricus
(much magnified).

14 MICKOBES, FERMENTS, AND MOULDS.

microbes, properly so called, are still often assigned to
the class of fungi. We shall speak of them separately,
and give our reasons for distinguishing them from
true fungi.

Hymenomycetes are the fungi which possess the
hymenium or umbrella; all the edible species are
included in this class, together with a great number
of extremely poisonous species. They are generally
of considerable size, and only a few among them are
true parasites ; they do not, therefore, enter into the
plan of this work, and, in spite of the interest they
present, we shall content ourselves with the brief
notice of them we have just given. The other groups
must, however, detain us longer.

II. THE BASIDIOMYCETES : UREDINETE, THE RUST OF
WHEAT AND GRASSES.

The name of cereal rust is given to a parasitic
affection caused by a minute microscopic fungus which
is developed on the leaves of wild and cultivated
grasses. This rust appears in the form of orange
patches, which gradually spread over the blades of
wheat and other grasses, and its common name is
due to this colour. Many of the plants belonging
to other families are attacked by analogous parasites,
and these fungi are all assigned by naturalists to
the genus Uredo, and to the family of the Basidio-
mycetes or Uredinece.

PARASITIC FUNGI AND MOULDS.

Basidiomycetes have no endogenous spores, but
they may have as many as four forms of exogenous
spores. This is the case with the rust of wheat,
termed by naturalists Uredo or Puccinia graminis,
which appears in the spring on the blades of this
plant. The patches of rust are covered with a fine
dust, which, under the microscope, is seen to consist
of small elongated bodies of a reddish brown, resting
on a filament; these are the first
spores of the fungus, and are
termed uredospores (Fig. 5). If
they are scattered over a blade
of wheat which was previously
healthy, they germinate by means
of a hypha of mycelium, which'
penetrates the leaf and develops
a fresh patch of rust. In harvest-
time the patches are of a darker,
almost black shade, owing to the
development of a second kind of
spore. These are pear-shaped,
divided in two, with an enveloping
membrane of considerable thickness; they are called
teleutospores (Fig. 5).

Teleutospores cannot germinate on a healthy blade
of wheat, and consequently do not communicate rust.
They may remain through the winter on thatch
or wheat straw, awaiting the ensuing spring, and
even then they cannot be developed upon a blade

Fig. 5.— Part of a patch of
Puccinia graminis, taken
from a blade of wheat, and
displaying several uredo-
spores and one teleutospore
(much magnified).

16 MICEOBES, FERMENTS, AND MOULDS.

of wheat, but only upon the leaves of another plant,
the barberry.

Borne by the dew or by a drop of rain on to the
young leaves of the barberry, the teleutospores germi-
nate, and form reddish-brown patches which affect
both sides of the leaf. On its lower surface the
spores are smaller, and are termed spermata; their
function is not thoroughly understood. The larger
spores on the upper ' surface are called cecidiospores
(Fig. 6), and with these we are more concerned, since

Fig. 6. — Section of a barberry-leaf bearing two cecidiospores, more or less developed,
of Puccinia graminis (much magnified).

they are destined to return to the wheat, rye, or other
grasses, in order to reproduce the original rust.

When they are placed on a blade of one or
other of these grasses, the oecidiospores germinate at
once, and it is soon covered with patches resembling
those of the preceding year; when these patches are
numerous, they dry up the blade and destroy the ear.

Hay and straw affected by rust should never be
given to animals as food, since such food may produce
disease.

Thus it appears that Puccinia graminis presents
the phenomenon of alternation of generations ; that is,

PAEASITIC FUNGI AND MOULDS. 17

the complete development of the fungus is only effected
by its transference from one plant to another. This
phenomenon may be frequently observed in animal
and vegetable parasites, and it seems to be designed
in order to secure the preservation of the parasitic
species, by permitting it to grow on two plants in
succession, of which the development occurs at different
periods of the year ; such is the case with the barberry,
which is developed in early spring, while wheat is
developed in summer. For a long while it was
believed that (Ecidium berberidis, Uredo linearis,
and Puccinia graminis were so many distinct
species; but it is now known, as we have stated,
that they are only three successive phases of the
development of a single species.*

Other Uredinece, constituting the modern varieties

>f Ustilago and Tilletia, are more apt to affect the

ears of wheat and other grasses. This disease is termed

>y agriculturists smut or caries (Uredo carbo or

rJstilago segetum, and Tilletia caries). The diseased

rrain merely appears to be of a somewhat darker

colour, but on pressing it between the fingers, there

ssues from it a blackish, oily pulp, which smells

ike rotten fish. Bread made from the flour of such

corn has an acrid and bitter taste, and although it

does not appear to be directly injurious to health,

* So, again, (Ecidium rliamni (Nerpmn or Bourdaine) produce
Uredo rubigo-vera and Puccinia coronata of wheat and oats. (Seo
Fig. 7.)

MICKOBES, FERMENTS, AND MOULDS.

it cannot be regarded as fit for food. The dust
arising from these fungi often produces in threshers
in a barn an irritating cough, which ceases when
they are no longer subject to the exciting cause.

The verdet, or, as the Italians call it, verderame of
maize is due to the presence of the same parasite
( Ustilago segetum, Uredo carbo, or Sporisorium maidis)
on the grains of maize, and for a long while it was
believed to produce pellagra, a common disease among
the peasants who live on maize. It is now known
that pellagra is due to the growth of another fungus,
much resembling the ergot of rye, of
which we shall speak presently.

Other species of Uredinece attack
sorghum, rice, etc., and, indeed, very
many plants are affected by parasitic
fungi belonging to the genus Puccinicu
and to allied genera, and it is probable
that they almost all present the phfc-
nomenon'of alternation of generations.
A simple means of freeing our fields from the rusi
of wheat is indicated by what we now know of the
alternation of generations which ensures the propaga-
tion of this fungus. We must destroy all the barberry
bushes which are found in the vicinity of cornfields
Popular opinion, although ignorant of the phenomenon
of alternation of generations, has long regarded the
neighbourhood of the barberry as the principal cause
of the rust of cereals.

Fig. 7. — Spores of
Uredo rubigo vera,
or Puccinia, coro-
nata.

PARASITIC FUNGI AND MOULDS. 19

In 1869, De Taste ascertained that in the parish of
Chambray, after the peasants had uprooted all the
barberries which grew in the hedges, the harvest,
which had been bad in the foregoing year, was
gathered in under normal conditions for three suc-
cessive years. After the Lyons Railway Company had
planted a barberry hedge to fence the railway in the
parish of Genlis (Cote-d'Or), the cornfields bordering
on the line were attacked by rust in an aggravated
form. An inquiry made by the company showed
that the disease was due to the barberry, and that
where that plant was not found, the wheat was not
affected by rust. On the other hand, a single shrub
of barberry caused the disease to appear in a field
in which it had never occurred before.

The smut of wheat may be destroyed by the
application of quicklime, either dry or dissolved in
water, which destroys the fungus or checks its develop-
ment. Seed corn should always be subjected to this
operation when affected by smut. In default of quick-
lime, sulphate of copper is sometimes used, which
may be injurious, or sulphate of soda, dissolved in
water (eight kilograms to the hectolitre). This should
be done the day before the seed is sown. In the case
of corn intended for food, another process called pelle-
tage must be employed; this consists in the frequent
stirring of the granaried corn, either with the hand
or with Vallery's movable granary floor, so as to dry
and aerate it, and expel the dust and damp, which are
favourable to the development of fungi.

20 MICROBES, FERMENTS, AND MOULDS.

III. ASCOMYCETES ; ERGOT OF RYE ; THE MOULD OF
LEATHER AND DRIED FRUITS.

In distinction from the species just described, the
fungi in this group possess endogenous spores, enclosed
in a sac or special envelope which is called an ascus ;
hence the name of the family. Truffles, or Tuberacece,
are only reproduced by the spores contained in these
asci; but most of the other ascomycetes present in
addition several forms of spores, and the phenomenon
of alternation of generations has led to the belief that
in this case, as in that of the foregoing group, many of
the so-called species are only successive transformations
of one and the same species. This is the case with
the ergot of rye, a product used in medicine; it is,
however, a serious and dangerous disease of several
of our cereals, and particularly of rye (Fig. 8).

Ergot is caused by a minute parasitic fungus which
attacks the ear of rye when it is in flower. The
young flower is covered with a white mass, consisting
of microscopic spores, formerly termed sphacelium
(Fig. 9). These spores reproduce themselves on other
flowers, and propagate the evil.

The mycelium formed by the germination of the
sphacelium affects the grain, forms in it a thick felt-
work, and is developed so as to constitute the elongated
substance termed sclerotis (on account of its hardness),
or ergot ; it is called at this stage Claviceps purpurea.

PARASITIC FUNGI AND MOULDS. 21

The sphacelium surrounding it falls off, and until the

9.— Sphacelium or
Claviceps purpurea,
the first stage of ergot
(magnified).

Fig. 8.— Ear of rye, on
which there are several
grains of ergo^

Fig 10.— Ergot bearing the organs
of fructification (magnified).

flowing spring the ergot remains stationary on the
ioil on which it has fallen.

MICKOBES, FERMENTS, AND MOULDS.

In the spring, owing to the heat and moisture, the
hyphae of the sclerotis swell and send forth numerous
branches, bearing at their ex-
tremity a sort of rounded head,
in which the asci or peritheces
are developed (Figs. 10, 11, 12);
the endogenous spores issuing
from these asci germinate on
the rye-blossom, and produce
there a fresh sphacelium, then
a second ergot, thus always
passing through the same cycle
of alternation of generations.
Most of the Graminacece and several Cyperacece are
capable of Droducing ergots resembling those of rye

Fig. 11.— One of the heads or
organs of fructification in
ergot, still more magnified,
a, peritheces.

Fig. 12.— Portion of preceding figure under a very high magnifying power, showing
at & the asci, and at c the spores issuing from the asci or peritheces.

and possessing the same medical properties. The sug-
gestion has been made that instead of the ergot of ryt

PARASITIC FUNGI AND MOULDS. 23

the ergot of wheat should be used in medicine ; it is
larger, harder, and more elongated in form, and it also
appears to be less perishable.

Ergot of rye, especially when powdered, strongly
resembles meat in smell, and only becomes unpleasant
when the powder is spoiled by being kept in a damp
place ; it then smells like rotten fish, and this is the
case with many other fungi.

At first the taste is not very apparent, but it after-
wards produces on the pharynx a somewhat persistent
sense of constriction. The chief action of this drug
consists in producing contraction of unstriated muscu-
lar fibres, especially those of the uterus. Ergotine
and ergotinine are extracted from it, and these, which
are its active principles, are often employed in thera-
peutics in preference to raw ergot.

In large doses ergot is a strong poison. It then
produces characteristic symptoms, dilatation of the
pupils, retardation of the circulation, vertigo, stupor,
and even death.

Bread made with flour from which the ergot has
not been extracted may produce the grave symptoms
known as ergotism, and these soon become fatal unless
the use of such bread is discontinued. Sometimes
nervous symptoms predominate, and this is termed
convulsive ergotism ; sometimes the disease takes the
form of gangrene of the extremities, or gangrenous
ergotism, but these two forms are only two phases of
one and the same disease, and often occur in the same

24 MICKOBES, FERMENTS, AND MOULDS.

individual. In countries where rye bread constitutes
the chief food of the rural populations, as in Brabant,
the north of France, Orleannais and Le Blaisois, fatal
epidemics have been recorded at different times in the
Middle Ages, under the name of St. Anthony's fire.
The first symptoms are a species of intoxication, sought
after by the peasants, and becoming habitual, like
alcoholic drunkenness, up to the moment when con-
vulsions and gangrene set in, and death soon follows.

Ergot of maize produces analogous phenomena. In
countries where maize bread and cakes are in use,
as in Italy and South America, it appears to be the
cause of the disease improperly called Pelade. Of this
the shedding of the hair and skin is the first symptom.*
Fowls which feed on ergotized maize lay eggs which are
devoid of shell, owing to their premature expulsion
from the uterus; their combs become black, shrivel,
and finally drop off; and they even shed their beaks.
All these phenomena may be easily explained by the
action of ergot on the muscular fibres of the uterus,
and of the blood-vessels.

Recent research has shown that Pelade is identical
in its cause and external symptoms with the disease
known in northern Italy and in the south of France as
pellagra, and in Spain as the rose sickness. The latter

* We shall presently see that the name Pelade was formerly given
to another parasitic affection, peculiar to that part of the skin covered
with hair. These two diseases must not be confounded, notwithstand-
ing the similarity of name, since they are produced by two fungi
belonging to different groups.

PARASITIC FUNGI AND MOULDS. 25

name is due to the red stains which cover the skin,
afterwards drying up and falling off in the form of
scales. At first the general health is not affected, and
several years may intervene before the occurrence of
vertigo, a want of appetite, emaciation, and finally the
torpor and convulsions which precede death. These ill
effects may be prevented by baking the maize before
grinding it, according to the process in use in Burgundy.

There is another very common fungus also belong-
ing to the group of ascomycetes, termed Eurotium
repens. This mould appears upon leather which has
been left in a damp place, and on vegetable or animal
substances in process of decomposition or badly pre-
served, and especially upon cooked fruits.

This mould is of a sombre green, a colour by no
means due to the presence of chlorophyl. On the
mycelium, which spreads over the substance of the
leather or of the fruit-skin, small stems are developed,
consisting of a jointed tube, and terminating in an
enlarged head on which chaplets of small grains are
formed, each of which is a spore. This was formerly
termed Aspergillus glaucus, and was regarded as a
peculiar species (Fig. 13).

When, however, this mould is developed in a place
in which the supply of air is limited, small gold-coloured
balls may often be observed beside or in the midst of the
stems, and these are filled with asci, each containing
eight spores. This second form has been termed Euro-
tium repens. It has recently been ascertained that

MICROBES, FERMENTS, AND MOULDS.

the balls in question are produced from the same
mycelium as Aspergillus glaucus, and that conse-
quently the chaplet of stalks and the balls filled with
asci are merely two organs of the same fungus.

Fig. 13. — Aspergillus glaucus, mould on leather and rotten fruits : a, hypha bearing
the chaplet of spores b ; c, a germinating spore ; d, ball of Eurotium ; e, ascus
enclosing the endogenous spores (magnified).

The chaplet of spores in Aspergillus glaucus repre-
sent the white exogenous spores, or the sphacelium of
the ergot of rye, and those which are subsequently

PAEASITIC FUNGI AND MOULDS. 27

produced in the yellow balls correspond with those
which issue from the asci developed on the sclerotis ;
these are endogenous spores.

Many of the parasitic fungi belonging to the genera
Erysiphe, Sphceria, Sordaria, Penicillium, etc., pre-
sent a similar mode of vegetation, and affect a large
number of plants. Such is the Oidium of the vine
(Erysiphe Tuckeri} to which we shall presently revert.

IV. OOMYCETES, MUCORINE.E, OR MOULDS, PROPERLY
SO CALLED ; PERONOSPORE.E ; THE POTATO-FUNGUS.

In all the parasitic fungi of which we have hitherto
spoken there is no sexual reproduction analogous to
that of the higher plants ; there are no male and female
organs comparable to the stamens and pistil. This
sexual reproduction exists in the oomycetes, although
only in a very elementary form. In
addition to the ordinary spores which
we have noticed in other fungi, there
are others termed oospores, which are
formed by the fusion of the originally
distinct contents of two different
cells. In the family of the mucorinege,
which includes most of the fungi
commonly called moulds (Fig. 14),
the two cells of which the contents
are fused together are similar. In the peronosporeae,
however, which includes the potato-fungus, one of the

MICROBES, FEEMENTS, AND MOULDS.

cells is larger than the other, and persists alone up to
the moment when the oospore is mature. It must,
therefore, be regarded as the female cell ; while the

Fig. 15.— Reproductive organs of Mucor mucedo (much magnified).

other, which is smaller and soon withers away, is the
male cell.

The mycelium of the oomycetes is developed in a
more or less liquid medium, like all other decomposing
and putrefying substances. The ordinary spores are

PARASITIC FUNGI AND MOULDS.

very small, and are formed within a small enlargement
(sporangium) borne on a free hypha of the mycelium.
Their succession is constant and numerous as long as
the plant is in a favourable medium in which it can
flourish. The spores which are found in the same
medium germinate, and reproduce a mycelium similar
to that from which they had their origin.

Fig. 16.— Reproductive organs of Peronospora calotheca (much magnified).

The oospores may be as much as a thousand times
larger in volume than ordinary spores. They are only
formed when the growth of the fungus is on the wane,
as, for instance, when the substance serving as a sup-
port to the mycelium is drying off: a long period may
elapse before they germinate (Figs. 15 and 16).

30 MICROBES, FERMENTS, AND MOULDS.

Fig. 15 represents the reproductive organs of
Mucor mucedo. 1 is the sporangium filled with
ordinary spores ; in 2, the wall of the sporangium
has disappeared, so as to show the free spores round
the central columella ; 3 and 4 represent the germina-
tion of these spores, giving forth their hyphae ; 5 gives
the conjugation of the sexual spores, which are fused
into one large oospore, 6 ; of this we see the germina-
tion in 7, and it produces a hypha terminating in a
sporangium.

Fig. 16 represents the same organs in a Perono-
spora. In 1 we see the mycelium of the fungus
penetrating the tissue of the infected plant; in 2,
the fructifying apparatus containing the ordinary
spores issues through a stoma, ramifies, and produces
sporangia at the extremity of each branch ; in 3 and
4 we see two spores which have issued from these
sporangia germinating and penetrating theVpidermis
of a leaf through the stomata (a, b) ; in 5 we see
the conjugation which has taken place between two
dissimilar cells : the male cell, smaller in size
(antheridium) is applied to the large female cells
(oogonium), and after this mode of fertilization it
is termed an oospore, which is represented in 6.

Mucor mucedo, and other species of the same
genus, form the small downy tufts of a greyish white
colour which may be observed on mouldy bread, rotten
fruits, and on the excrement of horses, dogs, and
rabbits. When examined under the microscope, the

PAKASITIC FUNGI AND MOULDS. 31

filaments of which these tufts consist display at their
extremities the sporangia represented in Fig. 15, 1.
On rotten fruits, the spores of these fungi germinate
in five or six hours by introducing their hyphse
through the epidermis. Sleepiness, which is only the
first stage of rottenness, is, according to Davaine,
to be ascribed to the action of these fungi. Fruit in
this mouldy condition is sometimes unwholesome.

The potato-fungus, Peronospora infestans, is one
of the most dreaded scourges of this valuable plant.
It attacks the lower surface of the leaves and stalks,
and appears in the month of July, in the form of
brown patches. The long hyphae penetrate deeply
beneath the epidermis, and will even propagate them-
selves on the tubers.

Among the causes which produce or promote this
disease, agriculturists place the excessive moisture
of the soil, setting the plants too late in the season,
the use of bad seed, the premature and exhausting
germination of the tubers before they are planted,
and the use of fresh dung which is not sufficiently
decomposed.

The following process is indicated as likely to
prevent the development of this parasite. In the
spring, the first protective ridge should be prepared
with a flat top, from eight to ten centimetres high,
and from twenty-five to thirty centimetres wide.
Tn the first fortnight of August, a second protective
ridge should be earthed up, of which the edge should

32 MICROBES, FERMENTS, AND MOULDS.

be acutely sloped, and the stalks of the plant should
be turned down into the furrow, so that any spores
which may be on the leaves may be washed off them
by the rain, and not come into contact with the stem
and roots of the plant.

It is probable that earth-worms diffuse the spores
of this fungus, as well of those of many other
microbes.

According to Prillieux, beetroot is attacked by
another species of Peronospora, which causes the
leaves of the plant to wither and fall. The remedy
consists in burning the dead leaves on which the
oospores remain during the winter, or, at any rate,
in not allowing them to be placed on the dung-heap.

The mildew which affects the vine is also a species
of Peronospora (P. viticola) as we are about to show.

V. PARASITIC FUNGI OF THE VINE: OIDIUM,
MILDEW, ETC.

The parasites of the vine are so numerous as to
require a separate chapter. Some years ago, in 1870,
fifty of them were enumerated Toy Roumeguere, a well-
known specialist, and the number is now more than
doubled. We shall only now speak of the more
important, of those which are especially injurious
to the vine, and which consequently are the most
interesting to us.

PARASITIC FUNGI AND MOULDS. 33

O'idium. — Oidium, or Erysiphe Tuckeri — so
called from the name of the vine-grower by whom
it was first described — has been longest known to
us among these parasitic fungi. It belongs to the
group of Ascomycetes, and appears to have reached
us from America in 1845, in which year it was first
observed in England. Thence it passed over to
France. In 1847 it was noticed in the neighbourhood
of Paris; and afterwards, in 1850-1851, in the south
of France, where for twenty-five or thirty years it
raged with such intensity as to threaten for some
years the almost complete destruction of the vine-
yards, a destruction which is now taking place under
the attacks of another parasite, belonging in this
instance to the animal kingdom: Phylloxera vastatrix.

The Oidium, the white disease or meunier, was
equally destructive in the vineyards of Madeira, so
that it was necessary to uproot all the vines, an<?
replace them by sound plants which were incapable
of bearing grapes for some years.

The oidium appears on the grape in the form
of greyish filaments, terminating in an enlarged head,
which contains an agglomeration of spores, not free
or in a chaplet, as in Aspergillus (Fig. 13). These
spores escape as fine dust, diffuse themselves in the
air, and spread the disease afar with extreme facility.

If a spore lodges on a vine-leaf under favourable
conditions of moisture and warmth, it soon germinates,
penetrates the epidermis by means of its hyphse, and

34 MICROBES, FERMENTS, AND MOULDS.

forms floury patches which send forth a peculiar
musty smell.

The oidium may remain latent on the vine-stock
throughout the winter. In the spring it reappears
in yellowish patches on the earliest leaves, on which
it is rapidly propagated ; the plant languishes, and
the leaves become pale and, as it were, anaemic.

Very dry weather is unfavourable to oidium, and
so also are heavy rains, which wash the fruit and
leaves, and carry away the spores on to the soil.

The remedy consists in the application of sulphur
to the infected vines. Flowers of sulphur is used,
which acts upon the fungus by gradually setting free
sulphurous acid. Under this influence the microscope
shows that the superficial mycelium and the fragile
spores dry up as if they were burnt (Ed. Andre*).
Three successive applications are necessary, and these
are made with the help of a special instrument in
the form of a pair of bellows, to which a rose is
affixed, in order to disseminate the flowers of sulphur.
The first application is made in spring, when the
shoots are from eight to ten centimetres long; the
second directly after the vine has blossomed; and
the third when the grapes begin to ripen. The opera-
tion in spring is the most important, and should be
performed with the utmost care, so as to affect all
the hybernating spores from which the succeeding
generations would issue. Not only the upper and
lower sides of the leaves must be dusted, but also

PARASITIC FUNGI AND MOULDS. 35

the branches and the stock itself. The third applica-
tion should be made early enough for the sulphur to
have disappeared from the grapes before the vintage
takes place, It is evident that its introduction into
the wine would have the worst effect : in process of
fermentation sulphuretted hydrogen would be given
off, which is injurious to the alcohol, and this gas
would give an unpleasant taste to the wine.

The morning is the best time for applying the
sulphur, since the dew enables the powder to stick
to the leaves and branches; and it should be made
on a fine day, since heavy rain would carry off the
sulphur before it has time to act upon the oidium.

The sulphur which ultimately reaches the soil
below the vine is transformed into sulphate of lime,
which is an excellent dressing for the vine.

Mildew. — This new parasite, of which the scientific
name is Peronospora mticola, belongs to the group
of Oomycetes. It also comes to us from America.
It was imported into Europe in 1878, with the
American plants destined to replace those destroyed
by the phylloxera, and was rapidly diffused through
France, and thence to Algeria. It appears in the
form of irregular patches of a whitish colour, not
very thick, and with an almost crystalline appear-
ance like that of a saline efflorescence (Planchon).
It has not the mouldy smell of oidium, and appears
later in the season, generally on the autumn shoots.
Its mycelium penetrates more deeply than that of

MICROBES, FERMENTS, AND MOULDS.

o'idium. Brown patches appear on the upper surface (
of the leaf, as if it had been scorched ; and in corre-1
spondence with these there is a delicate down " like
the whiteness of a slight hoar-frost " (Yaissier) on its
lower surface. The hyphse issuing from the mycelium
ramify at right angles, and these branches bear the
spores, as in the potato-fungus, Peronospora infestans
(Figs. 17, 18). These numerous spores, diffused through
the air, are powerful sources of contagion.

Fig. 17. — Mildew : a, vertical section of a leaf, bearing tufts of Peronospora viticola
on its lower surface; b, a withered leaf, bearing the winter spores (oospores)
( X 20 diam.).

This parasite destroys the tissue of the leaf,
exhausts it, and finally causes it to wither and fall.
Those which are least affected have only diseased
patches. The bunch of grapes and the young
herbaceous shoots are rarely affected.

In addition to the ordinary or summer spores of
which we have spoken, the sexual spores must be
noted ; the oospores, or dormant winter spores, which

PARASITIC FUNGI AND MOULDS.

hybernate in the tissue of the leaf itself (Fig. 17, 6),

and germinate in the spring. The conjugation of the

sexual spores, as well as the ripening of the summer

spores, and the germination

of the zoospores which issue

from them, can only occur in

a drop of water, rain, dew,

or mist, so that a persistent

drought checks the propagation

of this fungus.

The parasite injures the
stock by stripping it of its
leaves, thus hindering the nu-
trition of the plant ; moreover,
the grapes, since they are im-
perfectly protected from the

sun, dry up before they are Fig. is.— Group of tufts of Pero-
ripe. Sometimes, also, the
fungus attacks the grape itself,
or its peduncle.

Vines planted in a moist soil resist its attacks
better than others, simply because the nature of the
soil makes the plant more vigorous, and suitable
manure acts in the same way. When the fungus is
developed, it may be destroyed by sulphur mixed
with powdered lime. Since its mycelium is more
deeply seated than that of oidium, it is necessary
to have recourse to more vigorous measures in order
to reach it. Powdered borax has also been pre-

[g. 1O. VJlVUp Ul l/uifco v* -M.

nospora infestans, issuing from
a stoma on the lower surface of
the leaf and bearing the summer
spores (x 120 diam.).

38 MICROBES, FERMENTS, AND MOULDS.

scribed, in the proportion of five grammes to a litre
of water; also a solution of sulphate of iron, one
kilogram to two litres of water, with which the
stock should be washed fifteen days before the shoots
begin to start (Millardet). Mme. Ponsot, in Bordelais,
has used the same substance mixed with lime (four
parts of powdered sulphate of iron to twenty parts
of lime). The fallen leaves which contain the
winter spores, or oospores, should be burnt or buried.
The stocks should be irrigated as often as possible,
and the leaves should be dusted with lime in order
to dry off the dew or mist, which favours the fertili-
zation of the oospores.

Some species of vines resist the disease better
than others, and this is the case with the Labernet,
a vine from Me'doc, which has remained almost
entirely free from it in infected regions of Algeria.

Anthracnosis, or Black-rot. — This fungus, of which
the name is Phoma uvicola, or Sphaceloma ampelium,
belongs to the ascomycetes. Of all the parasites of
the vine it was the earliest known, but it was only
in 1878 that its devastations were important enough
to attract attention. Like the two preceding fungi,
it is reproduced by spores carried afar by the slightest
breeze. Heat and moisture are favourable to its pro-
pagation, which is checked by drought.

It appears on the young shoots in the month
of May, in the form of round black spots which
gradually spread over the twigs, leaves, and grapes.

PARASITIC FUNGI AND MOULDS. 39

The young stalks assume a sickly appearance, and
often wither off, together with the leaves and fruit.

When the fungus fastens on the fibro-vascular
bundles of the leaves before their complete develop-
ment, the leaves shrivel and curl up, and perform their
functions imperfectly ; when it attacks the petiole or
peduncle of the bunch of grapes, it dries up, and the
destruction of all the parts in dependence on it soon
follow. It is this fungus which, under the name of
rot, now devastates the American vineyards.

Sulphur is by no means so efficacious in this case
as it is with oidium, but the following treatment is
prescribed by Fortes : —

1. The prunings of the vine and other remains
of the preceding years should be destroyed, 2. The
suckers and young shoots should be dusted, in the
second fortnight of April, with slaked lime which has
been finely powdered, and this operation should be
repeated once a fortnight up to the end of June.
3. Sulphur should be applied at the usual times,
especially if there is any oidium. 4. The vines
should be drained and irrigated as often as possible.
5. In all cases in which the fungus can be detected,
powdered lime should be applied at the interval of
some days, alternately with the same substance mixed
with flowers of sulphur.

Aubernage, called by the Italians the Slack disease,
must not be confounded with Anthracnosis. Accord-
ing to recent researches, aubernage is not produced

40 MICROBES, FERMENTS, AND MOULDS.

by a fungus, but by a degeneration which is either
spontaneous or, as Pirotta and Cugini suggest, the
work of bacteria, and which consists in the trans-
formation of the cellulose and starch of the plant
into dextrine, as Comes asserts, or, according to Pirotta,
into tannin.

This disease appears in three stages : (1) a simple
discolouration of the sap, which assumes a tawny
black shade without checking vegetation ; (2) a begin-
ning of necrosis, which renders the plant unhealthy ;
(3) a complete necrosis, which affects the woody parts
and arrests the growth of the plant.

This disease is contagious, which leads us to
believe that if it is not produced by a fungus, it is
at any rate due to the development of a bacterium —
that is, of a microbe.

The remedy indicated by Italian naturalists con-
sists in the application of salts of potassium, which
may be extracted at small cost from the ashes of the
vine branches which are burnt upon the spot.

Rcesleria hypogea, or Rot. — This parasitic fungus is
found on the vine-roots, and has been recently studied
by Prillieux. The vine affected by this parasite
languishes for some years and then dies. The evil
spreads by means of the roots to adjoining stocks,
and the parts affected spread like the patches formed
by the phylloxera. The roots rot away. This disease
has been widely spread in Haute Marne.

This small fungus is distinct from one which bears

PAKASITIC FUNGI AND MOULDS. 41

the same French name, Pourridie, which is found
in the south of France, and has been studied by
Planchon and Millardet. These naturalists describe
it as formed by the rhizomorphous mycelium of
a large hymenomycetous fungus, Agaricus melleus.
Rcesleria is very different. It is a small white fun-
gus, with a white or ash-coloured head, from eight
to ten millimetres in size, of which the mycelium
lives in the interior of the vine-roots, penetrating
and profoundly affecting all the tissues of the roots,
and producing in the autumn the fructification which
comes to the surface.

It is generally developed in marly and argillaceous
soils, after a rainy season, and in the low-lying parts
of vineyards on the slope of a hill. It thrives in
the moisture which lies below the surface of the soil,
and it is therefore important to improve the con-
dition of those sub-soils which are impermeable.

It is also necessary to separate the stocks, so as
to prevent their roots from interlacing, and to uproot
and burn diseased vines, since the fungus may subsist
for several years in dead and dried roots. If, which
is almost always the case, any fragments of roots
remain in the ground, they will reinfect the sound
stocks which have been substituted for them.

Remarks on Diseases of the Vine. — We may be
surprised that this valuable plant, which has been
so carefully cultivated in France, should be attacked
by such a number of parasites, both animal and

42 MICKOBES, FERMENTS, AND MOULDS.

vegetable. Yet we should rather be surprised that
the vine has not been completely destroyed by the
combination of such diverse scourges, and that it has
effectually resisted them in several regions of France.
When we consider that for long years the same hoary
old stocks have been required to produce grapes
without truce or mercy, and often without taking
pains to supply to them by a fitting manure the
nourishment which is withdrawn from them by the
fructification of the grape, we shall be less astonished
at the decadence of our vineyards. And, indeed,
enlightened minds ascribe the attacks of these
numerous parasites to the weakness and exhaustion
of our vines, rather than to any accidental cause, such
as an importation from without.

The principal remedy may, therefore, be found in
restoring the strength of the vine by the planting of
young suckers, and still more of seedlings. Instead
of attempting to introduce foreign plants, which it
may not be easy to acclimatize, and which will
certainly be less valuable than the vines we have
lost, it would surely be better to seek to regenerate
our indigenous kinds by crossing the cultivated stocks
with wild vines, or else, as Millardet suggests, by
crossing them with each other. The attempt might
also be made to graft the stocks from Bordeaux and
Burgundy on wild or American vines, which offer
a better resistance to the attacks of the phylloxera.

PARASITIC FUNGI AND MOULDS. 43

VI HABITAT OF PARASITIC FUNGI: THEIR DESTRUC-
TIVE ACTION.

The habitat of parasitic fungi is extremely varied.
Roumeguere, in his Cryptogamie illustre'e, has devoted
more than forty pages of a large quarto, printed in
three columns, merely to the enumeration of fungi,
classified according to their position in plants, animals,
organic or inorganic substances, and the author himself
admits that this list is far from complete.

Parasitic fungi are found on plants belonging to
all the families of the vegetable kingdom, and also
on other fungi ; on living animals, vertebrate and
invertebrate ; on their dead bodies and on excrement ;
in stagnant waters and in the sea, on piles and rocks.
Others prefer marshes, turf-bogs, heathy ground (which
may be marshy or dry), dunes, caves and holes, and
even completely covered by the soil, as is the case
with truffles. Others, again, grow upon stones, walls,
and rocks ; in the open air or in ruins ; or, like Torula
conglutinata and Himantia cellaria, in the darkest
caves, where they form a species of feltwork, often
several centimetres in thickness, of a blackish colour,
ragged, and extremely light, which in the course of
a few years overspreads the walls of cellars. Other
fungi inhabit our houses, attack our food, clothes,
utensils of every kind; wall-papers and books, of
which the paste offers a nutriment which they can

44 MICROBES, FERMENTS, AND MOULDS.

easily assimilate ; linen ; and even our toilet sponges,
notwithstanding that they are in daily use. They
may even be found on the most powerful chemical
substances, on pastilles of sulphur, arsenical solu-
tions, etc.

" The general belief," writes Roumeguere, "regards
fungi as the result of decomposition. This belief is
due to an imperfect acquaintance with the nature of
these plants. Fungi are not only found on fragments
of wood and decayed vegetables, but sometimes even
on bare pebbles, on glass, on window-panes, on the
lenses of microscopes, and on other polished surfaces.
It must be supposed that fungi are able to extract
the elements of nutrition even in such positions.
Coprins, which have a surprising power of develop-
ment, grow on amputated limbs. Young has recorded
the appearance of a great number of these fungi, still
in an imperfectly developed state, below the mattress
on which a man was lying whose leg had been ampu-
tated. The bed was cleaned, and in nine or ten days
the fungus reappeared in the same abundance as
before. Targionni-Tozetti had previously observed a
similar growth on the apparatus which surrounded a
fractured limb in St. George's Hospital, Modena."

Berkeley states that immediately after the death
of any vegetable substance, an army of fungi of
various kinds is at hand to complete the work of
decomposition. The soft tissues are rapidly reduced
to a semi-fluid condition by the combined action of

PAEASITIC FUNGI AND MOULDS. 45

putrefaction and of these fungi. The hardest wood
yields to the same agents, not indeed so quickly, yet
much more rapidly than would be the case from the
action of the constituents of the atmosphere alone.
When a log of one of our finest trees is attacked by
fungi, it soon becomes only a mass of rotten wood,
of which the woody tissue has been traversed and
destroyed by the mycelium. If the same log were
merely subjected to the action of the weather, it
might endure for half a century before becoming
completely rotten.

Merulius destruens (or M. lacrymans) attacks
beams and the other pieces of wood used in building,
and rapidly destroys them. The administrators of the
Canal du Midi, Toulouse, were compelled to replace
the oak piles which protect the sides of the canal as
it traverses the town, on account of the ravages of
Dematium giganteum, one of the higher orders of
fungi in its early form. At the end of the last
century, the same fungus destroyed, in the course of
two or three years, the Foudroyant, a sixty-gun
vessel.

In order to stop the development of these fungi in
wood used for building, and especially in wood in-
tended for ship-building, it is expedient, as soon as
the trees are felled, to steep them in a metallic
antiseptic solution — as, for instance, in sulphate of
copper.

An experiment made by Nageli, a celebrated

MICKOBES, FEEMENTS, AND MOULDS.

botanist in Munich, demonstrates the action of micro-
scopic fungi on organic substances, exclusive of any
previous deterioration.

" I enclosed," he says, " several loaves in a tin case,
which was carefully but not hermetically closed.
When the case was opened at the end of eighteen
months, the loaves were reduced to a small mass,
consisting almost entirely of filaments of mould, in
which I could detect no trace of the substance of
bread. This mass was soft and moist, like a mud-pie.
It emitted a strong odour of trimethylamin : no trace
of starch remained. One hundred parts in weight
of the original bread were transformed into sixty-four
parts in their moist state, and seventeen parts after
desiccation in the open air. The
starch had been consumed in order
to form carbonic acid and water."

Badham sums up in a few
words the destructive effects of
microscopic fungi. " Mucor mu-
cedo," he writes, " devours our pre-
serves; Ascophora mucedo turns
our bread mouldy; Molinia is
nourished at the expense of our
fruits; Mucor herbarium destroys
the herbaria of botanists ; and
Clicetonium chartatum (Actino-
spora) develops itself on paper, on the insides of books,
and on their binding, when they come in contact with

Fig. 19. — Chcetonium char-
tatum, mould on paper.

PARASITIC FUNGI AND MOULDS. 47

a damp wall (Fig. 19). When beer or sweetmeats turn
sour, it is the work of a fungus."

VII. PARASITIC FUNGI OF INSECTS, REGARDED AS
ALLIES OF MAN.

Many microscopic fungi attack insects, both living
and dead. We have all seen the bodies
of flies still, sticking to the window-
pane or curtain, and surrounded by a
species of aureole formed by the growth
of a fungus, Penicillium racemosum,

or sometimes Sporendonema muscce or

Saprolegnia ferax, of the family of Oospores (Figs.

20, 21, 22).

Cordiceps attacks certain caterpillars of the genera
Cossus and Hepialus, when they are buried in the
sand before their metamorphosis into chrysalides, and
kills them by the development of its mycelium in
their tissue. These caterpillars may often be found,
bearing on their backs a fungus longer than them-,
selves (Fig. 23).

Sphceria militaris, a parasite to Bombyx pityocarpa,
the caterpillar found on pine-trees, represents one of
the few fungi which may be regarded as beneficial
to man, since it destroys multitudes of these cater-
pillars, and thus neutralizes the ravages caused by
their devouring the young shoots and pine needles.
In the Antilles there is a wasp called the vegetable

MICROBES, FERMENTS, AND MOULDS.

wasp, because it is attacked during its lifetime by
a fungus which it carries about for some time, and
which finally causes its death : this is Torrubia
spherocephala (Tulasne). ' Isaria sphingum, another

Fig. 21. — Two filaments of Sapro-
legnia containing spores (greatly
magnified).

Fig. 22.— Oogonium of Saprolegnia
surrounded by Antheridia (much
magnified).

species of the same genus, has been observed on the
back of a butterfly, which was poised upon a leaf as
if alive, and which was probably killed by the
development of the fungus.

These and other facts, not to speak of the
muscardine of silkworms, to which we shall return,

PARASITIC FUNGI AND MOULDS.

have given rise to a surmise that if we could discover
the parasitic fungus of the phylloxera, we might
transform it into a powerful auxiliary of agriculture,
since by its aid the parasitic insect which
now ravages our vineyards might be
destroyed.

From this point of view Giard
has observed several of these parasites
of insects, which he calls Entomo-
phthorece, from the name of their prin-
cipal genus, Entomophthora. Such is
E. rimosa, which attacks grasshop-
pers and the diptera of the genus
Chironomus, enveloping them in a thick
feltwork formed by the winter spores, Fig. 23— Butterfly-

nymph bearing a

and speedily killing them. In the cordiceps.
same manner Isaria pulveracea attacks Pyrrhocoris
apterus, an insect which is often injurious to our
kitchen gardens.

It has been asked whether Entomophthora Plan-
choni, the parasite of the aphis, might not also prey
upon the phylloxera, but the experiments made in
this direction have not hitherto been so successful as
to allow us to count on this means of averting the
scourge. With the same object, Hagen has suggested
the use of beer-yeast, which seems to have a destruc-
tive effect on insects, as it is developed in their tissues.

50 MICROBES, FERMENTS, AND MOULDS.

VIII. MUSCARDINE, THE DISEASE OF SILKWORMS.

Muscardine, which is caused by a true fungus,
Botrytis bassiana, must not be confounded with other
diseases which attack the silkworm, such, for instance,
as pebrin, which, as Pasteur asserts, is caused by a
bacterium, or, strictly speaking, a microbe, and, accord-
ing to the recent researches of Balbiani, by Psoro-
spermia. We shall presently revert to this disease.

Botrytis bassiana is a true mould, belonging to
the group of Oomycetes, and allied to the potato-
fungus, Peronospora. It is propagated by spores,
which, -when falling on a silkworm, germinate and
penetrate its body. A mycelium is then developed,
which may take possession of the whole caterpillar
without appearing externally. The germination is
rapid in proportion to the age of the silkworm.

When death has been caused by the develop-
ment of the mycelium, hyphse appear through the
animal's skin ; these soon bear white, chalky spores,
which are readily detached and float in the air in im-
palpable dust like smoke. The silkworms on which
the dust falls do not appear to be diseased, and eat
with avidity, but they die suddenly. It takes from
70 to 140 hours to develop the spores and spread
the contagion. It is difficult to free the breeding-
houses from all the silkworms which die in this
manner; those which die after having crawled up
to the heather to prepare for their transformation

PARASITIC FUNGI AND MOULDS. 51

into chrysalides are only thrown away when they are
found on removing the cocoons. The clouds of dust
dispersed by the silkworms perpetuate the disease
in the best-ordered factories. When the heather is
thrown out of window, and the rooms are swept to
get rid of the dust, the spores float in the air and
are dispersed by the wind.

Damp favours the development of the fungus, and
the introduction of healthy silkworms into an infected
breeding-house will not extirpate the disease. In order
to attain this object, it is necessary to get rid of all
the dead silkworms before the development of the
spores, and to destroy their bodies by burning them
with the heather, or with quicklime. The breeding-
houses should then be completely emptied, and the
compartments should be purified and disinfected in
the ordinary way by fumigation with sulphur, and
washed with chlorine water, before fresh silkworms are
placed in them.

IX. PARASITIC FUNGI OF THE SKIN AND Mucous
MEMBRANE OF MEN AND ANIMALS.

The skin-diseases of man and animals which are
termed tinea are caused by the presence of parasitic
fungi, just as the itch is produced by the presence
of animals belonging to the group Acarus. These
diseases are rendered eminently contagious by the
dissemination of the spores of these fungi, which will

52 MICROBES, FERMENTS, AND MOULDS.

germinate wherever the conditions of heat and moisture'
are favourable, even on a healthy skin, or where it is
only irritated by a simple scratch.

Ringworm, Achorion Schcenlenii, the fungus
which produces this disease on the parts of the
skin covered by hair, belongs to the same family as
oidium. Its mycelium produces hyphae, bearing
chaplets of spores, as in the Mucorinese, but there is
no true sporangium.

Fig. 24. — Achorion Schcenlenii, fungus of ringworm ( x 400 diam.) : a, spores ; b, chains
of spores ; c, mycelium.

They are found in abundance in spots of ringworm,
amidst the sulphur-coloured substance which carpets
them. If a morsel of this substance is dissolved in
ammonia, the fungus is detached, and may be observed
\mder the microscope, especially if care has been taken
to stain it brown by an aqueous solution of iodine
(Fig. 24).

PARASITIC FUNGI AND MOULDS.

The mycelium consists of elongated, cylindrical
articulations, which find their way among the cells of
the epidermis, especially in the vicinity of the edges
of the patch, and may penetrate deeply into the dermis
(Fig. 25). Some of the shorter filaments terminate in

Fig. 25. — Transverse section of skin, on the level of a spot of ringworm : a, epidermis ;
b. superficial layer of dermis ; c, deep layer of the dermis ; d d' mycelium with
spores.

chaplets of spores, which are successively detached
from the stem ; they are therefore found detached in
large numbers in the midst of the epidermic cells.
The centre of the patch is occupied by one or more still

54 MICEOBES, FERMENTS, AND MOULDS.

infected hairs, surrounded by spores; but, while the
centre is in process of healing, the fungus extends to
the periphery and continues to spread. The raised
surface of the patch is formed by this parasitic growth,
which forms a circular excrescence, always increasing
in size, while raising and thickening the epidermis.
The parts affected by the mycelium are characterized
by a slight suppuration throughout the patch; the
indurated tissue is gradually absorbed, leaving deep
scars which persist after a cure has been effected.

The mycelium is found on infected hairs between
the coats of their bulbous roots, while the numerous
spores are only found between the epidermic layers of
the hair.

This fungus may be inoculated in all parts of the
skin, but its favourite site is the head, where it pro-
duces the disease long known as ringworm, or favus.

It has been already said that fungi prey upon each
other. Thus Achorion has for a parasite Puccinia favi,
a minute fungus of a reddish-brown colour, which is
often developed on the whitish epidermic scales which
cover the mycelium on fresh spots of ringworm. The
same parasite has also been observed on Pityriasis.

Trichophyton tonsurans. — This fungus, allied to
the preceding, subsists likewise on skin covered with
hair, and produces tinea tonsurans.

It is formed of a mycelium with two sorts of
hyphse, some simply nutritive, others with short
articulations, separating into chaplets of rounded

PARASITIC FUNGI AND MOULDS. 55

spores, which are continually detached (Fig. 26). The

Fie 26 —Trichophyton tonsurans on the epidermic layers of a patch of circinnate
herpes: a, spores; b, mycelium with long articulations; c, mycelium with short
articulations ( x 400 diam.).

mycelium is often ramified, and penetrates within the
epidermic cells, especially at
the base of the hairs.

It is probably that the
parasitic Sycosis which affects
the beard, and circinnate
herpes, two other skin-diseases,
are only varieties of the same
disease. In fact, Cornil and

Ranvier have ascertained that if Trichophyton is in-
serted in the glabrous chin of a child, it will produce

56 MICROBES, FERMENTS, AND MOULDS.

herpes; and that parasitic herpes may also be pro-
duced on the back of the hand by the transference
of the fungus from a patch of Tinea tonsurans.

The fungus may be transmitted to cats, dogs, and
horses, who thus become agents of the contagion. A
fresh study of the disease has been recently made by
an Englishman, Dr. Thin, and he also regards it as
identical with herpes, or Tinea circinata.

According to this observer, the contagion is not
transmitted by floating spores, but only by direct
contact, and especially by the exchange of hats and
caps so common among school-children.

Experiments in artificial culture in milk, carrot-
juice, or aqueous humour show that the fungus cannot
be developed when the hair on which the spores are
is entirely submerged ; a certain degree of moisture is,
however, necessary, which is probably more frequently
found on children's heads. In adults, the bulbous root
of the hair is dryer between the follicle and the skin.
The parasite may be destroyed by causing an inflam-
mation of the part affected, since the serous effusion
thus produced places the hair in the same conditions
as in the culture-liquids in which it is completely
covered, and not floating.

Pityriasis versicolor is produced by a fungus
resembling the foregoing, termed Microsporon furfur.
It grows between the cells of the epidermis, and
effects their rapid degeneration. The hyphse have
long articulations, intermixed with round spores, not

PARASITIC FUNGI AND MOULDS.

arranged in a chaplet, but grouped below the
epidermis (Fig. 28). The development is very slow,

Fig. 2R.— Microsporon furfur : a, b, groups of spores; c, mycelium with long, trans-
parent, and curved articulations.

but the fact of its inoculation can be established, and
artificial cultures may be made.

In the two parasites of which we have now to speak

58 MICROBES, FERMENTS, AND MOULDS.

we cannot recognize any mycelium, and in this par-
ticular they are allied with the ferments, of which we
shall speak presently. The fungus consists of round
cells, which multiply by budding. De Lanessan
regards them as a separate group, to which he gives
the name of Microsporese, while he designates those
parasites of skin covered with hair which possess a
distinct mycelium under the name of Trichophyta.
The Pelade Fungus. — Pelade is another disease of

Fig. 29.— Pelade fungus : epidermic cells, charged with spores ( x 500 diam.).

the skin covered with hair, which is caused by Micro-
sporon Audouini, and which presents the characters
just indicated. It would, therefore, be an error to
give it fhe same generic name as Microsporon furfur,
a fungus of which the mycelium is well developed,
if the recent researches of Grawitz, to which we
shall presently return,* did not tend to show that
Microsporese and Trichophyta are only forms of the
same parasite in different phases.

* See chapter on Polymorphism of Microbes.

PARASITIC FUNGI AND MOULDS.

The pelade fungus develops in the superficial
horny layer of the epidermis, on the surface of the
epidermic cells, and in their interstices. It does not
penetrate the hair-follicles, and is only occasionally
found on the hairs, in which case it is fastened to the
detached pellicles of the epidermis, not to the interior

°J) <U>

0000 O

JL 40 3

Fig. 31.— Isolated spores, taken from
patches of pelade : 1, 2, 3, 4, large
spores ; 5, budding spores ; 6, 7. 8,
empty spores ; 9 to 12, small spores
(x 1000 diam.).

V\«. 30.— Hair affected by the

rapid progress of Pelade

! mnte. it is surrounded

by epidermic cells charged

with spores (x 208 diam.).

of the hair (Figs. 29, 30). It is composed entirely of
the round spores already described, which are re-
produced by budding (Fig. 31).

The Fungus qf Pityriasis capitis simplex. — It is
very similar to the foregoing, and is likewise seated

MICROBES, FERMENTS, AND MOULDS.

in the horny layer of the epidermis, on which it
produces a roughness in the form of dusty pellicles.
It penetrates the hair-follicles, but not deeply, and
only in the vicinity of the point at which they emerge.
The spores of which it entirely consists are generally
of an elongated form, and give off buds.

According to Mallassez, this fungus is the prin-
cipal cause of alopecia; that is, the shedding of

Fig. 32.— Epidermic cell of skin
covered with hair, affected by
Pityriasis simplex, and covered
with spores ( x 1000 diam.).

O O O 6

8 6 e *
8 8 6 <*

Fig. 33. — Isolated spores, taken
from pellicles of Pityriasis
capitis simplex: a, full spores;
6, empty spores ; c, full spores
budding ; d, the same empty
( x 1000 diam.).

hair, and the baldness which eventually ensues from
it. It acts in two ways : (1) its presence and multi-
plication disintegrate the epithelial layers; (2) the
foreign body irritates the epidermis, producing exces-
sive activity in the evolution of cells, and consequently
the incessant desguamation which is the most apparent
symptom of the disease. The shedding of hair is chiefly
due to obstruction in that portion of the hair-follicle
which underlies the orifice of the sebaceous glands, and

PAKASITIC FUNGI AND MOULDS. 61

this checks the regular development of the hair. The
consequent irritation of the follicle produces hyper-
trophy; this leads to the shrinking and finally to
the obliteration of the follicle, and after languishing
for a while, the hair falls off.

Thrush (Oidium albicans)* — This fungus generally
appears on the mucous membrane of the mouths of
infants, especially of those brought up by hand, and
which have been accustomed to the use of a sucker.
The saliva becomes acid, and the white spots which
constitute thrush (Fig. 34) appear in several places,
especially on the tongue, the gums, and the soft
palate.

This plant is composed of two elements: of hyphse,
and of spores, which adhere closely to the mucous
membrane. The spores become elongated and con-
verted into hyphse, which are segmented and ramified
as their length increases ; and they produce spores by
division of the terminal cell, or sometimes by endo-
genous formation within the hyphse.

Thrush sometimes occurs in adults in certain
diseases, such as phthisis and typhoid fever, especially
when the patient eats little and is imperfectly
nourished, which is frequently the case in serious or
protracted illness.

It is easy to destroy thrush by washing the
mouth with Vichy water, or a solution of bicarbonate

* Oidium albicans, Robin ; Saccharomyces albicans, Rees ; Sacch.
mycoderma, Grawitz. (See chapter on the Polymorphism of Microbes.)

MICROBES, FERMENTS, AND MOULDS.

of soda, which neutralizes the acidity of the saliva.
It is, above all, essential that the feeding-bottle, all
the utensils employed for the infant, and the infant
itself, should be kept perfectly clean; and, unfortu-
nately, this condition is too rarely fulfilled, especially

Fig. 34. — O'idium albicans, or Saccharomyces mycoderma : d, much-branched myce-
lium ; g, chaplet or torula of spores, giving birth at/, k to the mycelium.

among the working classes in towns, and districts in
which children are usually put out to nurse. The
feeding-bottle in use in such cases generally smells
so sour as to be offensive to every one who is not

PARASITIC FUNGI AND MOULDS. 63

accustomed to it, and under these conditions thrush
is almost certainly developed, so that few children
escape an attack. It is not generally dangerous, yet
it may, in some cases, compromise the health, and
even cause the death of the child. In addition to care
about cleanliness, a little pinch of bicarbonate of soda
may be put in the feeding-bottle; this prevents the
milk from turning sour.

Onychomycosis. — This disease, which attacks the
nails of men and the hoofs of uni-ungulates (the horse,
the ass, and the mule), is caused by a parasitic fungus
of the genus Achorion (A. keratophagus). In man it
is termed dry caries, and it is a fungus which is readily
transferred from man to the animals with which he
has to do, just as Achorion Schcenlenii of ringworm
passes from man to the dog, cat, rat, horse, ox, and
perhaps even to rabbits and gallinacese.

In uni-ungulates the fungus is introduced into the
cracked and superficial layer of the hoof through its
fissures. In order to destroy it, this external layer
must be removed, and for greater security an anti-
parasitic treatment should be used.

This remedy cannot be applied to the human subject
without causing considerable pain ; yet the nail may
be pared and scraped, and the anti-parasitic remedy
can then be applied.

Prevention and Cure of SJdn-diseases. — The general
custom of going to a common barber to have the hair
dressed or cut must conduce to the dissemination of

64 MICROBES, FERMENTS, AND MOULDS.

the fungi which attack those parts of the skin clothed
with hair ; the brush, the comb, or razor which passes
successively and on the same day over hundreds of
heads or chins must necessarily, if only in one case
out of ten, carry the spores of the parasite from one
person to another.

The parasitic diseases of the hair are extremely
persistent, and precautions as to cleanliness will not
always effect a cure. The mixtures sold by hair-
dressers under the name of capillary water, lotion to
eradicate scurf, etc., should all be rejected. Experience
shows that wetting the head often favours the
development of the fungus, which may, indeed, remain
stationary for two or three days, but which becomes
more vigorous as soon as the head is dry. Sulphur
and its compounds are successful in such cases, as
well as in the parasitic diseases of plants. It would
be best to apply this remedy in the form of a dry,
impalpable powder, as in the application of sulphur
to the vine, but this cannot be done without in-
conveniences to which the persons affected do not
readily submit ; it might, however, be tried by those
whose hair is naturally greasy. In other cases, and
especially in those in which the hair is dry, as it
usually is in persons affected by Pityriasis capitis,
pomades must be used, although it has been asserted,
but not proved, that fatty substances afford nourish-
ment to the fungus.

However this may be, the pomade for which we

PARASITIC FUNGI AND MOULDS. 65

subjoin the recipe has been very successful in pity-
riasis, and in all the infantile forms of ringworm,
including that which occurs in teething, and which
may be safely treated, in spite of prejudices to the
contrary :

Turbith mineral (tri-mercuric sulphate) ... 1 to 2 grs.
Benzoinated lard ... ... ... 15 grs.

This pomade is lemon-coloured; it will assume a
flesh-colour by the addition of a few drops of red
litmus, and may be scented to the taste of the person
who is to make use of it. In ordinary cases of
pityriasis, it need only be applied every eight or
fifteen days. It is indispensable to wash the combs
and brushes in a solution of potash or ammonia, lest
the benefit of the treatment should be lost by re-
infection. In the case of true ringworm, especially in
adults, a much more energetic treatment is necessary,
for which medical advice is required.

66 MICKOBES, FERMENTS, AND MOULDS.

CHAPTER II.

FERMENTS AND ARTIFICIAL FERMENTATIONS.

I. WHAT is FERMENTATION?

CHEMISTS define fermentation in these words : " Fer-
mentation takes place wherever an organic compound
undergoes changes of composition, under the influence
of a nitrogenous organic substance called a ferment,
which acts in small quantities and yields nothing to
the fermented substance " (A. Gautier).

This nitrogenous substance, termed a ferment, is
regarded by naturalists as an organized living being,
either animal or vegetable. This was demonstrated
by the researches of Cagnard de La Tour, of Turpin,
of Dumas, and more recently by the splendid achieve-
ments of Pasteur. It is now proved that the artificial
fermentation which takes place in the manufacture
of wine, beer, etc., is produced by small microscopic
plants, called ferments or yeast.

The chemical transformation resulting from them
might be obtained without the intervention of yeast,

FERMENTS AND ARTIFICIAL FERMENTATIONS. 67

properly so called, either by means of a nitrogenous
substance of animal origin (Berthelot), or by other
chemical and physical processes which we shall
presently mention. But it may be questioned whether
the nitrogenous substance of animal origin, which
Berthelot considers to be dead, does not contain a
living ferment. This is not admitted to be the case
by Bechamp, whose theory will be given further on.

Whenever fermentation is produced solely by the
influence of physical and chemical agents, the action
is very slow. But it is, on the other hand, very rapid
when effected by living ferments or yeast, and it is
also much less costly, so that the latter mode of
fermentation is preferred by manufacturers. Yeast is,
therefore, the true agent in artificial fermentations.

All the saccharine liquids which contain glucose or
grape sugar, or a sugar which can be transformed into
glucose, and also all nitrogenous substances, phos-
phates, and ammoniacal salts, produce alcohol at a
temperature varying between 25° and 100°, and the
yeast of beer (of which the spores are carried through
the air) appears and is developed at the same time;
this occurs in the juice of grapes, beetroot, sugar-
cane, etc. The alcoholic liquids thus produced are
then subjected to distillation in order to extract the
alcohol. The transformation of alcohol into vinegar
is produced by another ferment.

Fermentations are very common in nature. The
transformation of sugar into lactic, butyric, and

68 MICROBES, FERMENTS, AND MOULDS.

caproic acids, under the influence of nitrogenous
substances and of the air; the change into glucose
of gums, of starch, of dextrine, of sucrose, and mannite;
the transformation of these substances into each other
under the influence of living agents, or of those
belonging to a living organism; the transformation
of such glucosides as populin, salicin, tannin, etc.,
into sugar, or into neutral or acid substances; — all
these phenomena are fermentations (A. Gautier).

We may even go further. The germination of
seeds and the ripening of fruit are accompanied by
phenomena of the same order. In animals, gastric,
pancreatic, and intestinal digestion, together with other
changes connected with nutrition and assimilation
which take place in the blood and in all the organs,
may be considered as true fermentations. In this case
the cells of our tissues and the blood-corpuscles play
the part of yeast in effecting alcoholic fermentations.

Finally, the miasmatic, virulent, and contagious
diseases, which we shall study in another chapter,
are also caused by changes in the blood and in the
other fluids of the system, and should be considered
as fermentations, produced by minute microscopic
organisms analogous to ferments, and which are, as
we shall presently show, bacteria or microbes, strictly
so-called. The putrefaction of dead bodies is also
a fermentation.

We shall, in this place, only consider the fermen-
tations which are used in manufactures.

FERMENTS AND ARTIFICIAL FERMENTATIONS. 69

History. — The precise knowledge of the nature of
fermentation is of comparatively recent date. The
ancients, indeed, seem to have had an idea, however
vague, of this phenomenon, which was in their case
connected with the erroneous theory of spontaneous
generation. We all know the fable of the bees, born
from the putrefying body of a slain bull, which forms
one of the chief episodes of the Metamorphoses of
Ovid, and of the fourth book of Virgil's Georgics.
Aristotle says that, by means of heat, one living being
may have its birth in the corruption of another. . . .
Fermentation is, in fact, always accompanied by an
evolution of heat. The same idea was revived in the
Middle Ages, and during the Renaissance by alchemists
and physicians. Van Helmont, who lived early in
the seventeenth century, goes so far as to say, " It is
true that a ferment is sometimes so bold and enter-
prising as to form a living being. In this way,
lice, maggots, and bugs, our associates in misery,
have their birth, either within our bodies or in our
excrement. You need only close up a vessel full
of wheat with a dirty shirt, and you will see rats
engendered in it, the strange product of the smell
of wheat and of the animal ferment attached to the
shirt."

Beside these singularly rash and purely fanciful
assertions, which show that imagination was allowed
in those days to play a much too important part
in natural science, we find a theory of the fermenta-

70 MICROBES, FERMENTS, AND MOULDS.

tion in putrefying bodies which would not be rejected
by modern naturalists and chemists.

"After death . . . the foreign ferments, which are
always intent on change, are borne through the air
and introduce corruption into dead matter ... at
least, unless the flesh is combined with certain sub-
stances, such as sugar, honey, or salt. It is, therefore,
these ferments, attacking whatever matter is deprived
of life, which disintegrate and prepare it to receive a
new soul (or fresh life)."

Linnseus, again, says that " a certain number of
diseases result from animated, invisible particles, which
are dispersed through the air. . . ." Boerhave, in 1693,
distinguished three kinds of fermentation : alcoholic,
acetous, and putrefactive. But we must come down
to the beginning of this century in order to find more
definite ideas respecting the organic nature of ferments.

In 1813, a chemist called Astier asserted that
every kind of germ from which ferments proceed is
carried by the air; that this ferment, of animal
nature, is alive, and is nourished at the expense of
the sugar, and hence results disturbance of the
equilibrium between the elements of sugar.

Subsequently, in 1837, Cagnard de La Tour de-
clared yeast to be a collection of globules which are
multiplied by budding; and in the following year
Turpin described the yeast of beer as a vegetable,
microscopic organism, which he termed Torula cere-
visice (Fig. 35).

FERMENTS AND ARTIFICIAL FERMENTATIONS. 71

Chemists were at first unwilling to admit the
important part played by yeast in fermentations, and
in order to explain it, they assumed the existence
of a very obscure physico-chemical
phenomenon, to which the name
of catalysis, or action by presence,
was given. But in 1843 an illus-
trious French chemist, Dumas,
clearly explained the physiological

Fig. 35.— Tbrula (Saccha-

functlOn Of the living ferment, Or romyces) cerevisice, yeast

of beer (x 400 diam.).

yeast.

"Fermentations," he writes, "are always pheno-
mena of the same order as those which characterize
the regular accomplishment of the acts of animal life.
They take possession of complex, organic substances,
and unmake them suddenly or by degrees, restoring
them to the inorganic state. Several successive fer-
mentations are, indeed, often required to produce the
total effect. The ferment appears to be an organized
being ; . . . the part played by the ferment is played
by all animals, and by all but the green parts of
plants. All these beings and organs consume organic
substances, multiply and restore them to the simplest
forms of inorganic chemistry."

Finally, Pasteur's memorable labours, which he
began to publish in 1857, confirmed the new theory
of fermentation, which no one now doubts. Pasteur
states that every fermentation has its specific ferment ;
in all fermentations in which the presence of an or-

72 MICKOBES, FEKMENTS, AND MOULDS.

ganized ferment has been ascertained, that ferment is
necessary. This minute being produces the transforma-
tion which constitutes fermentation by breathing the
oxygen of the substance to be fermented, or by ap-
propriating for an instant the whole substance, then
destroying it by what may be termed the secretion
of the fermented products. Three things are necessary
for the development of the ferment: nitrogen in a
soluble condition, phosphoric acid, and a hydrocarbon
capable of fermentation (such as grape sugar). Finally,
every organized ferment of fermentation or putrefac-
tion is borne about in the air, as may be shown by
experiments.

II. VEGETABLE NATUEE OF FERMENTS OR YEAST.

Yeast, or ferments, are in their organization
closely allied to the fungi of which we spoke in the
preceding chapter under the name of Microsporon.
Many botanists still assign them to the class of fungi
under the name of Saccharomycetes ; yet, as they live
in liquids, or at any rate on damp substances, like the
Algse, which are species of water-fungi, it is now
almost agreed to place them in the same category as
the latter, which they resemble in their whole organi-
zation, except in the absence of chlorophyl. This
last characteristic, the only one by which they ap-
proximate to fungi, is common both to them and to
microbes or bacteria, which are only ferments of

FERMENTS AND ARTIFICIAL FERMENTATIONS. 73

smaller size, and which are now also placed in the
class of Algse. We shall return to this subject when
we come to speak of bacteria.

The structure of ferments is very simple : each
plant is generally composed of a single cell, spherical,
elliptical, or cylindrical, formed of a thin cell- wall, con-
taining a granular substance called protoplasm, which
is the essential part of the plant. These cells have an
average diameter of ten micro-millimetres. They
grow and bud, and when one of them reaches a certain
size, a median constriction occurs ; it divides into two
parts, resembling the mother cell, and these some-
times separate, sometimes remain united in a group
or chaplet (Fig. 35). This mode of multiplication
continues as long as the plant remains in a liquid
favourable to its nutrition. But if its development is
hindered, if, for example, the liquid dries up, the pro-
toplasm contained in each cell contracts, and is
transformed into one or more globules, which are
the spores or endogenous reproductive organs of the
plant. These spores may remain undeveloped for
a long while, may become perfectly dry, and may
even be subjected to a very high temperature, without
losing the power of germination when they are again
placed in conditions favourable to their development.
They then reproduce the plant from which they had
their birth, and are multiplied in the same manner.*

* For further details on ferments and fermentations, see
Schutzenberger's work on the subject.

74 MICROBES, FERMENTS, AND MOULDS.

III. WINE FERMENTS; ALCOHOLIC FERMENTATION.

The commonest ferment of wine is, according to
Pasteur, SaccharomyCes ellipso'ideus (Figs. 36, 37, 38),
which must not be confounded with Kutzing's
Cryptococcus vini, since the latter has nothing to do

Fig. 36. — Saccharomyces ellipsoideus, wine ferment, in process of budding
(x 600 diam.).

with alcoholic fermentation. This ferment is found
on the grape, and is thus introduced into the ferment-

Fig. 3l.—Sacch. ellipsoideus: Fig. 38.— Sacch. ellipso:ideus :

development of spores ( x germination of spores (x 400

400 diam.). diam.).

ing- vats. The adult cells are of an elliptic form, and
are six micro-millimetres in length, by four or five in
width. They bud, and are reproduced in the way
already indicated, which is common to all ferments.

FERMENTS AND AETIFICIAL FERMENTATIONS. 75

Sacch. Pastorianus (Rees) is probably only a
variety of the foregoing (Fig. 39), differing a little
in the form of the cells, which are elongated, pyriform,
or club-shaped.

Lastly, Sacch. conglomeratus is somewhat rare. It
is found in the grape-must when fermentation is
nearly over (Fig. 40). It is so called because the new
cells are conglomerated, instead of being arranged in
a chaplet.

We must now notice the other ferments which

Fig. 39.— Sacch. Pastori-
anus ( x 400 diam.).

Fig. 40.— Sacch. conglam- Fig. 41.— Sacch. exiguus
eratus ( x 600 diam.). ( x 350 diam.).

are found, like those given above, in fermented syrups,
and which may also produce the alcoholic fermenta-
tion of wine. Such is Sacch. exiguus (Fig. 41), of
which the cells are much smaller than in the fore-
going, since they are only three micro-millimetres
by two and a half micro-millimetres.

The apiculate ferment, of which Engel has made
a separate genus, under the name of Carpozyma
cupiculata, is the alcoholic ferment which appears to
be the most widely diffused in nature (Fig. 42). It
is found on all kinds of fruit, especially upon berries
and drupes, as well as upon most of the fruit-musts

76 MICROBES, FERMENTS, AND MOULDS.

which are in process of fermentation. It has likewise
been observed in Belgium upon beer. It is generally
the first to appear and bud in the must. Its name is

Pig. 42.— Sacch. apiculata (Carpotyma), ferment of fruits ( x 600 diam.).

due to the characteristic form of its cells, which are
formed like rape-seed, or apiculated at both extremi-
ties of their large axis.

In the fermented must of red wine we find,
together with Sacch. ellipsoideus, a somewhat dif-
ferent form, which is perhaps only a variety — Sacch.
Meesii.

We must also mention another alcoholic ferment,
Sacch. mycoderma, wine or beer flowers, which con-

Fig. 43.— Sacch. mycod&rma, or Fig. 44.— Different forms of Sacch.

wine-flowers ( x 350 diain.). mycoderma.

stitute the white pellicle often seen on bottled wine
(Figs. 43, 44). Pasteur has shown that, under certain

FERMENTS AND ARTIFICIAL FERMENTATIONS. 77

circumstances, Mycoderma vini can produce alcoholic
fermentation ; this is easily shown by adding it to a
saccharine solution, in which it soon produces fermenta-
tion. It appears on the surface of all alcoholic liquids
which are exposed to the air, when fermentation is
over or nearly over. Its growth is very rapid ; a few
cells are enough to cover the surface in the course of
forty-eight hours with a thin white or yellow pel-
licle, which is at first smooth, and then wrinkled. This
implies, according to Engel's estimate, that a single
cell has produced 35,000 others in this short time.

Most of these different forms are probably only
different stages of development of a limited number
of species, since ferments are as polymorphic as
microscopic fungi.

We have said that before they are found in the
must of wine or fruits, the ferments fasten in a
dormant state on the epidermis of the fruit, by which
means they are introduced into the liquid about to be
fermented. We see how the spores are transported
through the air until they rest on the downy surface
of a drupe or berry. But it has been asked what
becomes of this ferment between last year's vintage
and the succeeding summer, and in what way it
passes the winter.

According to Hansen's researches, Sacch. apiculata,
which is, for instance, found upon gooseberries, is
washed off them by the rain, dispersed by the wind,
and falls to the ground with the fruit, where it

78 MICKOBES, FERMENTS, AND MOULDS.

remains buried through, the winter as a dormant
spore, in order to return to the same fruit when it
has ripened in summer. It can only be borne
through the air when the ground is completely dried,

In the same way, the ferments of wine, after
having passed through the bodies of men and animals,
pass the winter on the dungheap. This revelation
may not be pleasing to drunkards, but it will not
surprise those who are acquainted with the habits of
cryptogams in general, and of fungi in particular.
Brefeld has found these ferments during the winter,
especially in the excrement of herbivorous animals,
and on the dungheap.

The manufacture of wine is too well known to
require description ; we need only remind our readers
that alcoholic fermentation essentially consists in the
transformation of glucose, or grape-sugar, into alcohol
and carbonic acid. The latter, given off in the form
of gas, produces the ebullition or effervescence which
characterizes fermentation, and to which its name is
due. Sugar or glucose is, therefore, the essential
nutriment of all yeast-plants, and the indispensable
element of these fermentations, of cider, beer, and all
fermented liquors, as well as of wine.

IV. BEEK- YEAST.

The yeast of beer, or Sacch. cerevisice, was the
earliest known and the most carefully observed of

FEKMENTS AND ARTIFICIAL FERMENTATIONS. 79

all the ferments, and may be regarded as the type of
the family. Its cells are round or oval, from eight
to nine micro-millimetres in their longest diameter,
isolated or united in pairs (Fig. 35).

When these cells are deposited in a saccharine
liquid, which is therefore susceptible to fermentation,
vesicular swellings, filled with protoplasm at the
expense of the mother cell, may be observed at one

Fig. 45.— Yeast of superior beer
budding (x 400 diam.).

Fig. 46.— Spores of beer-yeast, in
iifferent phases of development.

or two parts of the surface of the cell ; these swellings
increase, acquire the size of the mother cell, and then
contract at their base (Fig. 45). They generally arise
on the sides of the cell, more rarely on its extremities.
The new cells thus formed soon separate from the1
mother cell, and the protoplasm given up to its off-
spring by the latter is replaced by one or two empty
spaces, termed vacuoles. When yeast is not in a
liquid susceptible to fermentation, it can remain for
a longer or shorter time without modification. If
abruptly deprived of all nutriment, and especially of
sugar, and placed in a sufficiently moist atmosphere,

80 MICROBES, FERMENTS, AND MOULDS.

spores may be produced (Fig. 46). It is rather
difficult to perform the experiment with success; "the
ferment must be frequently washed with distilled
water, as it may otherwise putrefy, instead of fruc-
tifying (Schutzenberger).

Let us briefly describe the process by which the
fermented liquor termed beer is obtained. The barley
which constitutes its essential principle does not
contain sugar ; but when it has germinated it contains
a substance termed diastase, under the influence of
which the starch of barley can be converted into
glucose.

The barley, which has been moistened in order to
make it swell and germinate, is spread in a thin layer
on hurdles, at a temperature of about 15° : this opera-
tion is called malting. It is generally performed in
spring, in order to ensure the necessary warmth
and moisture, and March beer is considered the best.
When the sprout attains to two-thirds of the length
of the grain, germination is arrested by drying the
grains on a stove, and they are then ground to
powder and become malt. This malt is then steeped
in water at the temperature of 60° and by the
action ^of the diastase the starch becomes glucose.
This saccharine fluid or wort is boiled with hops,
which are now added, not only to give a bitter and
aromatic taste, but also to preserve it. This infusion
of malt and hops is concentrated and cooled, and beer-
yeast, the product of. previous operations, is added in

FERMENTS AND ARTIFICIAL FERMENTATIONS. 81

order to establish fermentation. The yeast is procured
by collecting the scum of fermented beer and straining
it into bags.

In Belgium, the wort is allowed to stand until the
spontaneous development of fermentation takes place ;
but in France and Germany the ferment is generally
added. In this case two methods are in use, fermenta-
tion from above, and fermentation from below ; and this
enables us to distinguish two kinds
of yeast, that of superior, and that of
inferior beer (Figs. 45, 47).

In superior beer, the saccharifica-
tion of the starch of malt is effected
by successive steepings in casks at
the relatively high temperature of
from 15° to 18°. As the yeast is
formed, it gradually issues from the
bung-holes in the upper part of the
cask; hence its name. In England, large open vats
are used : the yeast rises to the top, and is removed
with skimmers.

In the manufacture of inferior beer, saccharifica-
tion is effected by steeping the malt in open vats at
the lower temperature of from 12° to 14°. The
yeast is deposited at the bottom of the vats in a
doughy and tenacious mass. When the first and
most active fermentation is at an end, the clear liquid
is drawn off and put into casks, bottles, or pitchers,
and as the separation of the yeast is not yet complete,

Fig. 47.— Yeast of in-
ferior beer in process
of budding (x 400
diam.).

82 MICROBES, FERMENTS, AND MOULDS.

it continues to act on the unmodified sugar. The
production of fresh yeast makes the liquor thick, and
the amount of alcohol and of carbonic acid increases
in accordance with the time for which it is kept, after
being bottled or put in closed casks.

The manufacture of most fermented liquors
resembles that of wine or beer ; that of cider is very
simple, and consequently approximates to the manu-
facture of wine. The apples are cut and crushed, and
remain in the vats until fermentation is over; the
liquid is then separated from the solid residue, and
put into casks or bottles.

V. CONCERNING SOME OTHER FERMENTED LIQUORS.

There are many other fermented liquors made in
various countries with substances derived from the
animal or vegetable kingdom.

In France, cider or perry is sometimes made from
pears or crab-apples.

What the French call boissons are cheap fermented
liquors, prepared from dried raisins or aromatic sub-
stances, such as the dried fruit of the coriander, to
which water sweetened with treacle is added. Fer-
mentation is usually effected by germs borne by the
air, or by those introduced by the coriander and the
other ingredients of the liquor ; or it may be hastened,
as in Belgian beer, by the addition of beer-yeast or
baker's yeast. It is effected by the transformation of

FERMENTS AND ARTIFICIAL FERMENTATIONS. 83

the sugar into alcohol and carbonic acid, and this con-
stitutes an aerated drink, which is very agreeable when
well made, and especially if it has been carefully
bottled before fermentation is over.

Koumiss is made of soured and fermented mare's
milk, and is much used in Eussia as a refreshing
drink, from which an alcoholic liquor may be distilled.

Many kinds of brandy are made from the fruits
and seeds of different plants. Kirschwasser is the
alcohol produced by distilling cherries or geans ; rum
is made from sugar-cane, arrack from rice. Gin,
distilled from the juniper-berry, is largely consumed
by the labouring classes in England, as corn-brandy is
in the French drinking-shops.

The savage Malay and Polynesian races prepare
fermented liquors from the sap of various plants.
Such is kava, made from masticated roots, and steeped
in an infusion of Piper methysticum. In this case,
the ptzalin, a ferment contained in the human
saliva, transforms the fecula into a sugar susceptible
to fermentation. The operators sit round a large
vessel containing the roots steeped in water, and each
man takes a piece, which he masticates conscientiously
until it is sufficiently impregnated with the salivary
ferment. This process is revolting to our ideas, and
few Europeans would touch a liquor which has been
prepared in such a way; but this is doubtless an
educated prejudice which would not occur to a native
of Oceana.

84 MICEOBES, FERMENTS, AND MOULDS.

The dragon-trees (Draccena terminalis and D.
Australis) also possess a feculent root, from which a
fermented liquor is extracted in the same manner by
the Sandwich Islanders.

VI. THE LEAVEN OF BREAD.

Bread is leavened in order to make it porous and
more digestible. According to Engel, the microbe of
baker's yeast is Sacch. minor, resembling that of beer-
yeast, only more minute. Most of the yeasts which
we have examined contain a great variety of microbes.
However this may be, the fermentation of bread, like
other fermentations, sets free carbonic acid gas, and
this raises the dough and makes it light.

CHAPTER III.

MICROBES, STRICTLY SO CALLED, OR BACTERIA.

I. THE VEGETABLE NATURE OF MICROBES.

As we have seen in the preceding chapter, there is
no well-defined limit between ferments and bacteria,
any more than between ferments and fungi, or, again,
between fungi and bacteria. Their smaller size is the
principal difference which separates bacteria from
ferments, since in other respects these two classes are
for the most part alike in form and organization. There
are bacteria of large size, such as Leptothrix buccalis,
so frequently found in the mouth even of a healthy
man, which much resembles in its mode of growth
some of the lower fungi, such as Oidium albicans.
Yet the latter is regarded as a fungus, and the former
as an alga, by our best cryptogamous botanists. It
may, however, be said that the two classes of algae and
fungi are connected with each other by their lower
forms, and probably have a common origin ; just as the
two great organic kingdoms are connected by their

86 MICKOBES, FERMENTS, AND MOULDS.

lower forms, which have been by some united in the
kingdom Protista.

Microbes, or bacteria (Schizophyta or Schizomycetes),
appear, in liquids examined under the microscope, as
small cells of a spherical, oval, or cylindrical shape,
sometimes detached, sometimes united in pairs, or
in articulated chains and chaplets (Fig.
48). The diameter of the largest of these
cells is two micro-millimetres, and that
of the smallest is a fourth of that size,
so that at least 500 of the former and
200° of the latter must be placed end
fer0entnformesdof to end in order to attain the length of

bacteria, detach- .,.. TA • • i «» 1-^1

ed or in chapiets a millimetre. It is tneretore plain that a

(highly magni-
fied), magnifying power of 500 to 1000 dia-
meters, or even still higher, is required to make these
beings clearly visible under the microscope.

One very common bacterium may be found every-
where, and can be easily procured for microscopic
observation : Bacterium termo, or the microbe of im-
pure water. This bacterium is not injurious to health
since there is no potable water in which it is noi
found in greater or less quantity. In order to obtain
numerous specimens, it is enough to take half a glass
of ordinary water from a spring or river, and to leave
it for some days on a table or chimney-piece, the
vessel being uncovered to allow the access of air. We
may soon observe that a thin coating is formed on
the surface of the water, which looks like a deposit

MICROBES, OR BACTERIA." 87

of fine dust ; this dust consists of myriads of bacteria.
If we take a drop of this water and place it under
a cover-glass, in order to examine it under a micro-
scope with a magnifying power of about 500 dia-
meters, we shall, as soon as the instrument is properly
focussed, see a really surprising spectacle.

The whole field of the microscope is in motion;
hundreds of bacteria, resembling minute transparent
worms, are swimming in every direction with an un-

» \

f * V

Fig. 49.— &aet. termo in different stages of development, a-h (much magnified).

dulatory motion like that of an eel or snake. Some
are detached, others united in pairs, others in chains
or chaplets or cylindrical rods which are partitioned
or articulated (Fig. 49) ; these are only less mature or
younger than the first. Finally, we see a multitude of
small globules which result from the rupture of the
chaplets. All these forms represent the different
transformations of Bacterium termo, or the microbe of

88 MICROBES, FERMENTS, AND MOULDS.

putrefaction. Those which are dead appear as small,
rigid, and immovable rods.

In observing the lively movements of these minute
organisms, we might be tempted to regard them as
animals. But we know that movement, taken by
itself, is not peculiar to the animal kingdom. Setting
aside the movement which can be provoked in the
mimosa and in many higher plants, it is well to
remember that many of the lower plants are capable
of motion : this is the case with Diatomacece, in which
the presence of chlorophyl incontestably proves their
vegetable nature. The spores of plants of a much
higher organization, such as ferns and mosses, have the
power of swimming in the water, just as bacteria have :
this has procured for them the name of Zoospores,
although many of them contain chlorophyl.

The movements of bacteria are, like those of zoo-
spores, due to the presence of vibrating cilia, which
are inserted at both extremities, or only at the hinder
extremity of the microbe, and which form organs of
propulsion analogous to the tails of tadpoles. These
organs are very transparent and are difficult to see in
the living subject, even with the strongest magnifying
power, on account of the rapidity of their movements.
But their existence has been ascertained by the use of
staining fluids, and above all by micro-photography.

If, however, we analyze the mode of motion in
Bacterium termo, and compare it with the movements
of the ciliated or flagellated infusoria which may often

MICKOBES, OB BACTERIA. 89

be seen swimming with it in the field of the microscope,
we are struck by the difference. Infusoria come and
go, swiftly or slowly — they go back or move to the
right or left ; in a word, their movements seem to be
actuated in some sense by will. Nothing like this
is observed in the bacterium. The undulatory move-
ment by which it is animated is always the same, and
impels it straightforward, like a stone sent from a
sling ; it never voluntarily goes back nor out of its
course, but only under the influence of a foreign im-
pulse, such as contact with another bacterium, when it
rebounds, just as a projectile may rebound from a wall.
On encountering an obstacle, the bacterium remains
indefinitely undulating before it, without ever pausing
or showing signs of fatigue, until some external cause
comes to release and send it to the right or left. We
may often see a tangled mass of bacteria, perhaps
adhering by their cilia or by some other substance, in
which all the individuals continue to undulate until
the rupture of the mass permits them to depart in all
directions. These organisms are therefore plants in the
character of their movements, as well as in the rest of
their organization.

In bacteria each cell consists of a cellulose wall,
containing protoplasm, as we saw was the case in fer-
ments. The multiplication by fission is effected in
precisely the same way in bacteria and ferments, and
so also is the formation of spores. Under certain
circumstances, when the liquid on which they subsist

90 MICKOBES, FERMENTS, AND MOULDS.

is dried up, the protoplasm contracts and forms spores,
which, when set at liberty by the rupture of the cell-
wall, germinate and give birth to fresh bacteria. The
only difference consists in the fact that ferments may
produce several spores in each cell, while bacteria
never produce more than one.

Bacteria were, as we have already said, for a long
while classed with fungi under the name Schizomycetes.
But recent researches into their organization, and more
especially into their mode of reproduction, show that
they resemble a group of inferior algae termed Phy-
cocliromyceoe, which includes Oscillaria, Nostocs, and
Chroococcus, species generally furnished with chloro-
phyl. Bacteria represent a similar group devoid of
chlorophyl. Zopf, in a treatise recently published, goes
still further : he asserts that the same species of alga
may at one time be presented in the form of a plant
living freely in water or damp ground by means of
chlorophyllaceous protoplasm, and at another in the
form of a bacterium or parasitic microbe, devoid of
chlorophyl, and nourished at the expense of organic
substances which have been previously elaborated by
animals or plants, thus accommodating itself, accord-
ing to circumstances, to two very different modes of
existence.

MICKOBES, OB BACTERIA. 91

II. CLASSIFICATION OF MICROBES, OR BACTERIA.

It is very difficult to make any natural classifica-
tion of the organisms which belong to the group of
microbes ; we have, in fact, seen that they only differ
from each other in external form, and that these forms
are very variable, since the same organism may present
itself successively as an isolated globule, a chaplet, a
chain, and a more or less articulated rod. Microbes are
essentially polymorphous, and adapt themselves to
varied conditions of existence, which influence the
form taken by these microscopic organisms. For this
reason their classification has often varied, their dis-
tinction into genera and species does not yet rely on
precise data, and the opinions formed by various
authors in accordance with their personal researches
still differ widely.

We will, however, subjoin Wunsche's classification.

Schizophyta, or Schizomycetes.

A. Division of cells always occurring in the same direc-
tion, so as to form a chaplet before the joints
or members separate.

1. Cells united in mucilaginous or gelatinous families,
a. Cells united (in a state of repose) in amorphous

families.

o. Spherical or elliptic cells, colourless and gene-
rally motionless Micrococcus.

/3. Cells elongated in short, movable rods ... Bacterium,

"b. Cells united in families with sharp outlines, lobu-

lated and agglutinated like frog-spawn ... Ascococcus.

2. Cells arranged in filaments.

92 MICROBES, FERMENTS, AND MOULDS.

a. Cylindrical filaments, indistinctly articulated, mo-

tionless.
a. Unramified, very slender filaments :

(1) Short Bacillus.

(2) Long Leptothrix.

)8. Filaments repeatedly bifurcated (false ramifi-
cations) Cladothrix.

b. Spiral, movable filaments :

(1) Short, faintly undulated Spirochoete.

(2) Long, flexible Vibrio.

(3) Short, rigid Spirillum.

(4) Rolled into mucilaginous mass Myconostoc,

B. Cells dividing cross-wise, and the daughter cells re-
maining united, like packets tied with a crossed

cord Sarcina.

Most of the microbes of which we have now to speak
may be assigned to one or other of the genera given in
this scientific enumeration, and sometimes, on account
of their polymorphism, to several of these genera.

Before making a more detailed study of some of
them, it may be interesting to glance at them as a
whole, following the order of classification given above.

The genus Micrococcus (Hallier) includes the
spherical microbes, which are the most common and
the most widely diffused, probably because the spores

^ and early stages of all' the other forms

have this spherical shape before be-
• coming elongated and assuming their

. °c+ • adult form (Fig. 50).

Fig. 50. -Microbes Thls g6I1US ls Divided into two

^otccuKmS S sections i the first includes Micro-

coccuus chromogenis, i.e. fabricators of

colouring matter — an extremely interesting group, on

MICROBES, OE BACTERIA. 93

which we must say a few words, since these microbes
play an important part in nature, connected with
hygiene and domestic economy ; the second section
includes Micrococcus pathogenis, or the producers of
disease, which must detain us longer.

The genus Bacterium, of which the name indicates
that it is rod-shaped, also includes some coloured
species and more which are colourless,' such as the
bacteria of putrefaction, of stagnant waters, of vegetable
infusions, etc. (Fig. 49).

The genus Ascococcus is less common. The cells,
united in groups or families, form mucilaginous,
wrinkled membranes on the surface of putrefying
liquids, on the juice of meat, on the infusion of
hay, etc.

Bacillus (or Bacteridice, Davaine) forms an ex-
tremely important genus, characterized by its long,
flexible, and articulated filaments ; this genus includes
the butyric ferment, and the microbe which produces
the disease called anthrax, or splenic fever.

Leptothrix buccalis is found in the human saliva
and between the teeth (Fig. 51, k).

Cladothrix dichotoma forms a kind of fine grass,
which appears like a whitish mucilage on the surface
of putrefying liquids (Fig. 51, p).

Vibrio rugula and V. serpens are found in
infusions in the form of tolerably thick filaments,
which have only one inflection, while their successors
are spirally curved (Fig. 51, I).

MICROBES, FERMENTS, AND MOULDS.

Spirillum and Spirochoete only differ from each
other in the number and approximation of their
spirals. Spirochoete Obermeieri is found in the blood
of those affected by recurrent fever; S. plicatile,
which is found in stagnant water, amid Oscillaria, is

Fig. 51. — Different forms of microbes, or bacteria: a, &, c, d, Micrwoccus of various
forms ; e, the short Bacterium ; f, the short Bacillus ; k, teptothrix or long
bacillus: I, Vibrio, dividing by fission; m, Spirillum; o, Spirochoste; p, Clado-
thrix, etc. (from Zopf : highly magnified).

perhaps only the parasitic form of those algas, and
has often been regarded as the cause of marsh fever.
Spirillum is also found in infusions (Fig. 51, m, o).

Finally, Sarcina ventriculi, so different in form
from other microbes, is found in the fluids of the
human stomach, in the blood, and in the lungs, in the

MICEOBES, OR BACTERIA. 95

form of yellow patches. It is also found in the albu-
men of boiled eggs, in potatoes, etc. (Fig. 52).

©O

Fig. 52.— Sarcina ventriculi, in different degrees of development
(strongly magnified).

III. THE MICROBE OF VINEGAR, AND ACETIC
FERMENTATION.

Pasteur has shown that the acid fermentation of
alcoholic liquids is due to the existence of a special
microbe, acting like a ferment, which is developed on
the surface of fermented liquors whenever they are
abandoned to the contact of the air, in the presence of
albuminoid substances. This microbe, which consti-
tutes the mother of vinegar, and which is termed
Mycoderma aceti, is probably identical with Bacterium
lineola, so often present in infusions, in stagnant
pools, and even in spring water. It is a true
bacterium (Fig. 48).

The membrane which may be observed on the
surface of liquids in course of acetic, fermentation is
formed of very minute elongated cells, from To to 3
micro-millimetres in length, united in the form of

96 MICKOBES, FERMENTS, AND MOULDS.

chains or curved rods. They multiply by the trans-
verse fission of the cell, a fission preceded by a median
constriction. These are characteristics of the bac-
terium, strictly so called.

The nutrition of this microbe resembles that of
beer-yeast : it requires mineral salts, phosphates of the
alkaline metals and of the metals of the alkaline
earths, proteid matters, or ammoniacal salts.

This ferment is an oxidizing ferment, which with-
draws oxygen from the air and transfers it to the
alcohol, thus converting it into acetic acid ; hence it
can only subsist in contact with the air, and perishes
when it is submerged, so that acetification is then
arrested. The oxidizing power of this microbe is
such that it can even oxidize alcohol and transform it
into carbonic acid gas — a fact which explains how the
strength of wine is lowered by the other and larger
species, Mycoderma vini, of which we have given an
illustration (Figs. 43, 44). This action is less lively
in the presence of a considerable quantity of vinegar,
and at Orleans acetification is always effected in vats
which contain a large amount.

What is called the Orleans process, which is the
one generally employed in France, consists in filling
tuns which can hold about 200 litres with 100 litres
of vinegar and 10 litres of white or red wine ; once a
week 10 litres of vinegar are drawn off, and replaced
by 10 litres of wine. The temperature should be
about 30°. Oxygen is supplied by a proper system of

MICROBES, OR BACTERIA. 97

ventilation. This process is somewhat slow, since it
only produces ten litres of vinegar out of each tun in
the course of the week, and it has the disadvantage
of encouraging the multiplication of anguillidce, the
small nematoid worms which live in vinegar and sour
paste.

Pasteur has modified and improved the original
process so as to obviate both inconveniences. He
employs heat, which allows the process of acetification
to be intermittent, and thus prevents the development
of the anguillidce. Shallow vats, about 30 centi-
metres in depth, with lids in which holes have been
pierced, are used, and mycodei^ma is scattered on their
surface. Gutta-percha tubes, pierced with holes at
their lower extremity, are placed at the bottom of
these vats, so that fresh liquid can be added without
disturbing the superficial film of mycoderma.

In Germany, vinegar is made by means of spongy
platinum, or platinum black, which oxidizes alcohol
without the intervention of a microbe. This affords
a good example of fermentation, or of an analogous
phenomenon, produced solely by physico-chemical
action. The platinum black acts by disintegrating
the alcohol and placing it in more intimate contact
with the oxgyen of the air, since the process of
oxidation would be much slower without either this
process or the presence of the ferment.

98 MICROBES, FERMENTS, AND MOULDS.

IV. THE MICROBES WHICH AFFECT WINE.

The affections to which some wines are subject
alter their taste and quality so as often to render
them unfit for use. These affections ought to be
recognized, so that a diseased wine may not be con-
founded with one which is adulterated, and it is by
means of the microscope that we are enabled to
recognize the nature of these changes. Chaptal for-
merly ascribed them to the presence of an excess of
ferment, since he was unable to discover any other
cause. We now know from Pasteur's valuable re-
searches, published in his book, Etudes sur les vins,
that they are all due to the presence of microbes
peculiar to each disease.

" The source of the diseases which affect wine,"
Pasteur writes, " consists in the presence of parasitic
microscopic plants, which are found in wine under
conditions favourable to its development, and which
change its nature either by the withdrawal of what
they take for their own nutriment, or still more by
the formation of fresh products which are due to the
multiplication of these parasites in the wine." These
diseases are known under -fehe names of acescence,
pousse, graisse, amertume, etc. We shall review them
in succession.

Mouldy or Flowered Wine. — These are wines on the
surface of which white pellicles are formed (fleurs de
viri), which consist of Mycoderma vini (Figs. 43, 53).

MICROBES, OR BACTERIA.

This product does not turn the wine sour, nor sensibly
affect it. It is due to the temperature of the casks
being too high during the hot season. It may be
obviated by sprinkling them with cold water, or by
putting ice into them; care must also be taken to
keep the casks full, and the cellars as cool as possible.
Acidity of Wines ; Soured Wines. — Wine always

Fig. 53.— The disease acescence, which sours wine. Deposit seen in the microscope ;
1, 1, Mycoderma vim; 2, 2, Mycoderma, aceti, still young; 3, the same older, when
the mischief is at an advanced stage.

contains a small quantity of acetic acid, and when
this acid is in excess, the wine is no longer drinkable,
and turns to vinegar. This change is due to the
presence of Mycoderma aceti (Fig. 53), of which we
have already spoken. It is much more minute than
'M. vini, and takes the form of the figure 8, as the
illustration shows, or of chaplets formed by the union

100 MICROBES, FERMENTS, AND MOULDS.

of several 8's placed end to end. As they grow older,
the two globules of the 8 divide, and appear as isolated
granules. These two species of Mycoderma are in-
compatible, and are never found in the same wine.

The acid may be isolated by distilling the sour
wine. The attempt has been made to cure or im-
prove sour wine by adding normal potassium tartrate
(from 200 to 400 grammes to every hogshead of 230
litres), which forms potassium acetate and bitartrate
by neutralizing the excess of acid. The bitartrate is
deposited spontaneously, and crystallizes. Carbonate
of lime cannot be employed for the same purpose,
since it would spoil the wine.

Wines that are turned or over-fermented (vins
pousse's ; vins bleus). — This disease displays the follow-
ing characters : the wine assumes a bluish or brown
colour, and becomes turbid ; if shaken in a test-tube,
we may observe silky waves floating in every
direction. When a cask is tapped, the wine spurts
up, and it is said " qu'il a la pousse" If poured
into a glass, a number of minute bubbles appear on
the surface, the discolouration increases, and the wine
becomes more turbid. The taste is changed and
becomes insipid, as if water had been added. The
disease is developed in very hot weather (Chevalier
and Baudrimont).

This affection is due to the presence of an ex-
tremely attenuated microbe, somewhat resembling
that of lactic acid, which we shall ^describe presently,

MICEOBES, OR BACTERIA. 101

but differing from the latter in its undivided filaments.
Its diameter is at the most one micro-millimetre : it
varies in length, and is flexible, in which it resembles
the genus Vibrio. These filaments collect in a
mucous deposit at the bottom of the cask (Fig. 54).

Wine undergoes successive changes under the in-
fluence of this pathogenic ferment, and this has led

Fig. 54. — "Wines affected by pousse. Deposit seen under the microscope : 1, ordinary
alcoholic wine-ferment ; 2, acicular crystals of potassium bitartrate ; 3, crystals
of normal calcium tartrate ; 4, Vibrio, or microbe which produces the disease.

to the belief that there are several distinct diseases ;
hence the different names which have been given to
this affection.

The remedies for the disease consist in the ad-
dition of tartaric acid ; in drawing off the wine into
sulphured casks, and adding a little brandy ; and in
taking care to keep the cellars whitewashed and airy.

102 MICROBES, FEKMENTS, AND MOULDS.

Wine affected by Bopiness. — White wines, and
especially champagne, are more often affected by this
disease than red wines. It is more apt to attack wine
which has little alcohol and is deficient in tannin,
and under its influence the liquor becomes turbid, flat,
and insipid, ropy, like white of egg, and it loses its
sugar.

This change is effected by a filamentous microbe,

Fig. 55.— Disease of ropiness in wine, affecting champagne, and caused by a bacterium
which assumes two forms : the figure 8, and chaplets.

even more like the lactic ferment (Fig. 58) than the
one we have just described, since it is likewise formed
of very minute globules, united in chaplets, which
are, however, more attenuated than those of the lactic
ferment. These filaments form a species of feltwork
through which the liquid slowly filters; hence its
oily appearance. It is probably a bacterium (Fig. 55).

MICROBES, OR BACTERIA. 103

This ferment may be destroyed by tannin (15
grammes to a hogshead), which has the effect of pre-
cipitating it. Very ripe sorbs, which have been crushed,
may also be used for this purpose, as well as gall-
nuts and grape-seeds which have been ground to
powder ; all substances rich in tannin. The precipitate
thus formed should be separated from the wine by
refining.

Wines affected by Bitterness. — This disease affects
red wines, especially those of the choicest vintages
of Burgundy. Pasteur writes that "at its outset
the wine assumes a peculiar smell, its colour is less
vivid, and its taste becomes insipid. Soon the wine
becomes bitter, and there is a slight taste of fermen-
tation, due to the presence of carbonic acid gas.
Finally, the disease becomes more aggravated, the
colouring matter is completely changed, and the wine
is no longer drinkable."

The microbe which is the essential cause of this
disease is seen under the microscope in the form of
articulated filaments, curled back or bent, and it may,
or may not, be invested with the colouring matter of
the wine. It is reproduced by fission, not by bud-
ding. It is probably a bacillus (Fig. 56).

This ferment must not be confounded with that
of wine affected by pousse, of which the filaments are
much more slender, the articulations are hardly apparent,
and they are not incrusted with colouring matter.
Pousse is readily developed in wines of inferior quality,

104 MICROBES, FERMENTS, AND MOULDS.

while the finer sorts are more often attacked by
bitterness.

The bitterness may be to some extent neutralized
by the addition of new and sweet wines, but the
application of lime (from 25 to 50 centigrammes the

Fig. 56.— Bitter disease of wine. Deposit under the microscope : 1, 2, filaments of the
microbe (Bacillus} which produces the disease, mixed with crystals of tartar and
colouring matter (Bordeaux wine) ; 3, young microbes in an active state ; 4, dead
microbes, incrusted with colouring matter.

litre) is more recommended. This treatment mast,
however, make the. wine sour.

The deposits formed in deteriorating or old wines
are not effected by the microbes which we have just
enumerated, but are due, according to Pasteur, to
the combination of oxygen with the wine under the
action of time. This constitutes the aging of wine.

Viscous Fermentation of Saccharine Liquids. —
What is termed viscous fermentation takes place in the

MICROBES, OB BACTERIA. 105

juice of beetroots, carrots, and onions, and in liquids
containing sugar and nitrogenous substances. It is
probably produced by the same ferment which causes
the ropiness of wine (Fig. 55), and the liquid assumes
a viscous or oily appearance.

Pasteur states that this microbe acts on the glucose
and transforms it into gum or dextrine, into mannite
and carbonic acid. The lactic and butyric fermenta-
tions, which are often simultaneously produced in
saccharine liquids, are due to distinct microbes.

V. THE MICROBE OF LACTIC FERMENTATION.

The sugar contained in milk, as well as grape
sugar, can be transformed into lactic acid. This
transformation is always caused by the presence of
a ferment with which Pasteur has made us ac-
quainted. It had been previously supposed that milk
turned sour spontaneously when it was allowed to
stand for some days. In this case, as we know, the
milk curdles, and the clear liquid which separates
from the curd is called whey. In 1780, Scheele, the
celebrated Swedish chemist, extracted lactic acid from
whey. The same acid is also found in sour-crout;
in the sour water of starch ; in baker's yeast ; in water
in which peas, beans, or rice have been boiled, and then
suffered to ferment ; and, finally, in the juice of beet-
root which has passed through viscous and alcoholic

106 MICROBES, FERMENTS, AND MOULDS.

fermentation, after which it turns sour and produces
lactic acid and mannite.

Lactic fermentation requires the presence of pro-
teid matters in process of decomposition, and it can
only be carried on when the degree of acidity in the
liquid does not exceed definite limits. For this purpose
a certain amount of chalk is added, to neutralize the
acid formed at the expense of the sugar.

It is somewhat difficult to observe the microbe of
this fermentation without previous instruction. It
appears in the form of grey patches, which are readily
confounded with casein, and with the disintegrated
gluten, or the chalk of the liquid under examination.

Fig. 57.— Lactic ferment in a Fig. 58.— Lactic ferment

chaplet (Schutzenberger). (Pasteur).

Under the microscope the patch is seen to consist of
minute globules, or of filaments with very short articu-
lations, isolated or in flakes. These are the characters
of the genus Bacterium (Figs. 57, 58). The globules
are much more minute than those of the yeast of beer,
and are strongly agitated when in isolation by a
motion incorrectly termed Brownian movement, and
which does not in reality differ from the movements
which may be observed in most of the spores of the
lower orders of plants, and in a great number of
bacteria.

MICROBES, OR BACTERIA. 107

This ferment is often found in wine, together with
those of yeast and alcohol, and produces in it an in-
cipient lactic fermentation. The predominance of one
of these fermentations depends on the composition
of the medium, which may be more or less adapted
to them. A slightly alkaline medium is most suitable
for the lactic microbe, while in a perfectly neutral
medium only alcoholic fermentation will occur.

We have already said that mare's milk can be
transformed into an alcoholic liquid called koumiss.

VI. THE AMMONIACAL FERMENTATION OF URINE.

Shortly after its discharge, urine which is left to
itself assumes an ammoniacal odour. This is due
to the transformation of the urea (the nitrogenous
principle of urine) into ammonia and carbonic acid,
under the influence of a microbe which appears in
the form of free globules, of articulated filaments
(Torula), or of chaplets, resembling those of the lactic
ferment. This microbe is found in the white deposit
which collects at the bottom of vessels, and has been
termed Micrococcus ureas (Fig. 59).

This ferment is conveyed through the air, like
other microbes of fermentation. It does not exist in
the bladder as long as the urine remains acid. Yet,
in the rare cases in which urine has been found to be
alkaline, immediately after its issue from the bladder,

108 MICROBES, FERMENTS, AND MOULDS.

it may be ascertained that the ferment was introduced
by some accidental cause, such as a surgical examina-
tion, and that the sound served to convey the microbe.
It is, in any case, sufficiently common at the exterior
orifice of the urethra, and at the depth of two or three
centimetres.

Yon Tieghem has shown by precise experiments

Fig. 59. — Micrococcus urea (Von Tieghem). Microbe of ammoniacal fermentation.
It may be observed that the bacterium is in the figure 8, or in chaplets. (Much
magnified.)

that the presence of this microbe is the true cause of
the ammoniacal fermentation of urine. With certain
precautions, the urine withdrawn from a healthy
bladder may be preserved for an indefinite time.

These experiments have been recently resumed by
Sternberg, an American physician, who has clearly
demonstrated that only the microbes of the air, or

MICROBES, OR BACTERIA. 109

those of the orifice of the urethra, can produce this
fermentation. Since the latter are always carried off
by the first discharge of urine, only the second por-
tions of the emitted liquid should be collected in
a perfectly clear vessel, which has been sterilized,
or, carefully freed from all atmospheric germs. The
vessel should then be put under a glass shade to
protect it from these germs, and if all proper pre-
cautions are taken, the urine will remain clear and
acid for an indefinite time without undergoing am-
moniacal fermentation. If afterwards a little plug
of amianthus, which has been previously sterilized
by heat, should be introduced by a small pair of
pincers into the urethra to a depth of two centi-
metres, and then dropped into this untransformed
urine, it will soon be transformed, and undergo arn-
moniacal fermentation. But if the plug of amianthus
has been steeped in an antiseptic solution (diluted
carbolic acid) before being introduced into the urethra,
it will not produce this fermentation.

VII. BUTYRIC FERMENTATION OF BUTTER, CHEESE,
AND MILK.

Butyric fermentation follows lactic fermentation in
milk, butter, and cheese, and it is butyric acid which
gives to butter its rancid taste. This fermentation
also occurs in saccharine substances, and generally
in all proteid substances.

110 MICROBES, FERMENTS, AND MOULDS.

Pasteur has ascertained that this fermentation
results from the development of a microbe which
takes the form of minute cylindrical rods, rounded at
their extremities, usually straight, and either isolated
or united in chains of two or more articulations.
These rods are about two micro-millimetres in width,
and from two to twenty micro-millimetres in length.
They advance with a gliding motion, are often curved,
and present slight undulations. They are reproduced
by fission. These characters are those of the genus
bacillus.

Coagulation of Milk : Cheese. — The coagulation of
milk is artificially produced by rennet, the liquid
secreted in a calf's stomach. Human gastric juice
produces the same effect, and the milk introduced as
an aliment into the stomach is never digested until it
has been curdled, both in children and adults. The
artichoke flower, and other plants of the genus Car-
duus, will also curdle milk at a temperature between
30° and 50°. It is probable that this
action is due to the presence of an
organized ferment (animal or vege-
table cells), which here supplies the
place of the microbe of lactic fermen-

agent in the fabrica-

tion of cheese. tatlOn.

It is with rennet, or with the still more active
liquid produced by the maceration of the testicle of an
unweaned calf, that those cheeses are made which
consist only of curd, boiled or unboiled, fresh or fer-

MICROBES, OR BACTERIA. Ill

mented, and obtained from the milk of cows, sheep,
or goats, skimmed or unskimmed, according to the
kind of cheese desired.

Sweet-milk cheese do not differ in their composi-
tion from those of curdled milk. They consist of casein,
albuminoid matter which encloses particles of butter :
the liquid residue is the serum or whey, which con-
tains lactic acid and mineral salts.

Cheese, strictly so called, such as Gruyere and
Roquefort, only differ from the foregoing because they
have been exposed for a shorter or longer time to the
action of the air, and of the microbes suspended in it.
Cheese is first oxidized under the influence of the
oxygen of the air ; butyric and even alcoholic fermen-
tation soon follows lactic fermentation, together with
the disengagement of hydrogen and of putrid pro-
ducts, when the action of the ferments which effect
these transformations has gone on too long.

In order to obtain the different kinds of cheese
which come into the market, they are exposed to the
weather, generally in holes which have been excavated
in the rock for this purpose, on a bed of straw, or
sometimes partially covered with it, until the cheese
is ripe and has attained the desired quality.

Butyric and ammoniacal fermentations lead us
directly to the study of putrefaction ; that is, the fer-
mentation of dead organic matter.

112 MICKOBES, FERMENTS, AND MOULDS.

VIII PUTREFACTION, OK THE FERMENTATION OF
DEAD ORGANIC MATTER; A GAME FLAVOUR.

The flesh of animals used for food is said to be
high in the first stage of alteration which occurs when
it is left to itself. Pasteur does not believe that this
effect is produced by the intervention of the ferments
of the air, although this is the case with the putrefac-
tion which follows. He thinks that it merely results
from the action of what are called soluble or natural
ferments in the serum of the meat, and that there is
a chemical, reciprocal reaction of the liquids and solids
which are withdrawn from the normal action of vital
nutrition. This explanation is adapted to satisfy those
epicures who have a taste for high game and not for
microbes. Yet it is certain that this condition passes
into true putrefaction without any abrupt transition,
and we know that immediately after death the microbes,
which penetrate everywhere, take possession of the
animal tissues and begin their work of destruction.
"When flesh is high, it is therefore probable that it
is in the first stage of putrefaction.

Gautier has made some experiments on the sub-
ject, and holds that this condition is certainly due
to the action of microbes, and consequently to germs
in the air. In fact, meat which is placed in a soldered
and air-tight case after it has been deprived of germs
by a suitable process, is devoid of any high odour at

MICROBES, OR BACTERIA. 113

the end of six months, and is as fit for food as freshly
killed meat.

However this may be, meat which is high is
usually not injurious, while putrefied meat produces
diarrhoea or still more serious illness. Davaine has
shown that the septic properties of decomposed blood
are not removed by subjecting it to a temperature
of 100°, which destroys the microbes, but not their
germs or spores; for the destruction of the latter a
still higher temperature is necessary.

For a long while it was believed that the putrefac-
tion of dead bodies, and of albuminoid substances,
either animal or vegetable, which have been exposed
to a moist air at a temperature of from 15° to 30°, was
merely due to the instability of the organic compounds;
these, when left to themselves, tend, under the influence
of oxygen, to produce more stable compounds by dis-
integration and successive oxidations. Pasteur has,
however, shown that in this case also there is a true
fermentation; that is, a decomposition produced by
the vital action of certain microbes.

In general, when organic animal substances are
exposed to the air, they are in the first instance
rapidly covered with moulds; they lose their co-
herence, and after the lapse of a few days give off
fetid effluvia. Carbonic acid, nitrogen, hydrogen,
carburetted, sulphuretted, and phosphoretted hydro-
gens, are freely disengaged, and at the same time they
combine with the oxygen of the air. The microbes,

114 MICROBES, FEEMENTS, AND MOULDS.

which appear simultaneously with the moulds, pene-
trate deeply into the tissues, disintegrate them by
feeding at their expense, and the putrid condition
increases ; then the decomposition changes its nature
and becomes less intense. The putrefied matter is
finally desiccated, and leaves a brown mass — a complex
mixture of substances combined with water (hydro-
carbons), and of fatty and mineral substances which
gradually disappear by slow oxidation (Gautier).

Pasteur has ascertained, from the microscopic

Fig. 61.— Bacilli of pu-
trefaction (Rosenbach:
much magnified ) -pig. 62.—Zoogloea of Spirillum tenue.

study of the phenomena which occur in an infusion
of animal matter in process of decomposition, that
microbes appear in it in the form of globules or
short rods (Micrococcus, Bacterium termo, Bacillus,
etc.), which are either free or collected in a semi-
mucilaginous mass, to which the special name zoogloea
was at first given (Fig. 62). These microbes rapidly
deprive the liquid of all its oxygen. At the same
time a thin layer of mucedinece and of bacteria is

MICROBES, OR BACTERIA. 115

found on the surface, which also absorb this gas and
do not allow it to penetrate into the lower part of
the liquid.

This liquid now becomes the seat of two very
distinct actions. In its interior, vibriones succeed to
the free globules and zoogloea, of which they appear
to be only a higher stage of transformation. These
microbes multiply and change the albuminoid matter
into more simple substances ; insoluble cellulose, fatty
bodies, and gaseous putrid matters. Meanwhile, the
microbes on the surface actively consume the products
thus developed, transforming them into carbonic acid,
nitrogen, and the oxides of nitrogen, etc. This ex-
plains why, when there is an insufficiency of oxygen,
putrefaction may indeed begin ; but it languishes, and
is finally arrested.

The cause of the fetid odours which escape from
putrefying bodies and liquids is not well understood.
It may be ascribed to the disengaged gases (carburetted,
phosphoretted and sulphuretted hydrogen, and ammo-
niacal compounds), and to the circulation of decom-
posing organic particles. We also find formic, acetic,
lactic, butyric, valerianic, and capro'ic acids, generally
combined with ammonia, and the fatty acids which
are one result of the successive disintegrations of
albuminoid matters.

When these gases are disengaged, a substance
remains which may be compared with humus, or
vegetable earth. It is rich in fats, in earthy and

116 MICROBES, FERMENTS, AND MOULDS.

ammoniacal salts, and consequently constitutes a
strong manure, very fit to serve as the nutriment of
plants.

This is at once the beginning and the termination
of the endless chain which sustains the equilibrium
of nature, in which there is no creation, no destruction.
Plants draw their nutriment from the soil and the air
in the form of mineral solutions, and are devoured
by animals or by other parasites ; animals are in their
turn devoured by microscopic plants or microbes, and
return by means of putrefaction to the condition of
mineral salts, which are distributed in the soil, and
serve anew for the nutrition of plants.

We must at the same time be struck by the
resemblance which exists between these phenomena
of putrid fermentation, and those which occur in the
fermentations which accompany the nutrition of
animals and plants. Germination and the different
digestions which occur in the mouth, the stomach,
the intestines, etc., are only fermentations, so that
Mitscheiiich has paraphrased the Scripture saying,
"Dust thou art, and unto dust thou shalt return,"
by declaring that " Life is only a corruption."

It should, however, be remembered that fermenta-
tions are essentially phenomena of disintegration,
which always reduce complex, organic substances to
those which are simpler. Plants provided with
chlorophyl, on the other hand, alone possess the
property of forming higher organic compounds, by

MICROBES, OR BACTERIA. 117

the aid of purely inorganic substances. Animals and
plants devoid of chlorophyl get their nutriment by
unmaking the complex substances elaborated by the
green parts of plants, and these act in the same way
for their own profit in those organs which have no
chlorophyl ; as, for instance, in the seed and embryo.

IX. — AEROBIES AND ANAEROBIES.

We have seen that microbes, at different epochs
of their existence, and in accordance with the nature
of their environment, can assume very diverse forms.
Thus the organism, which at first appears in the form
of globules (micrococcus), either isolated or united in
more or less numerous colonies by a kind of muci-
laginous envelope (Zoogloea), when it again becomes
free, may be elongated in the shape of the figure 8,
which is formed of two cells about to separate; or
a large number may be included in the form of a
straight, articulated rod (Bacterium), or in a rod
which is curved, waved, or even spiral (Vibrio,
Spirillum, Spirochcete), always more or less mobile;
or, again, the cells may form long, stationary filaments
(Bacillus), etc.

So also the habitat and mode of life divide the
microbes into very distinct classes. Some can only
subsist when they breathe the natural oxygen they
withdraw from the atmosphere; they can only exist

118

MICROBES, FERMENTS, AND MOULDS.

on the surface of liquids, or of the organic substances
on which they feed. These are termed aerobics,
or consumers of air. Others, again, can live beneath
the surface of liquids and in living organisms, or of
those in process of decomposition, and must neces-
sarily derive the oxygen necessary for their respira-
tion from the oxygenated substances in which they
are found. These are termed anaerobies.

am p

Fig. 63.— Vibrio rugula in different stages of development (anaerobie), much enlarged.

This distinction and the theory on which it relies
have been introduced into science by Pasteur, and
they appear to be founded on observed facts. Thus
Bacterium termo, which lives on the surface of putre-
fying liquids, is an aerobie ; while Vibrio rugula
(Fig. 63), which lives below the surface of the liquid,
below the layer formed by the Bacterium termo , is an
anaerobie, and derives its oxygen from the water or
solid matters which are found in it in suspension or
solution, and even from other microbes. So, again,
the yeast of superior beer is an aerobie, and the yeast
of inferior beer is an anaerobie, etc. Paul Bert regards

MICROBES, OK BACTERIA. 119

the corpuscles of the blood, and the cells of which all
our tissues consist, as true anaerobic microbes ; so
likewise are the microbes which, when introduced into
the blood, are the cause of certain diseases. The
important consequences of this fact, which it is neces-
sary to note, will appear presently.

X. — THE MICROBES OF SULPHUROUS WATERS.

The formation of the sulphurous springs which
are so numerous in the Pyrenees and in other parts
of France, appears to be due to the presence of small

algae of the family Oscil-

latoria, and of the genera

Oscillaria and Beggiatoa

(Fig. 64). These microbes c- ;^jibsg II

are of the same structure Fig> ^_Beggiatoa ^ ^

as those of which we have sulphurous 8pring8.

spoken above, but they contain chlorophyl, and also
a blue colouring matter. They are placed in the
group Cyanophycece, which, as Zopf believes, contains
species that are sometimes green, and sometimes
colourless, like Bacillus and Leptothrix, which they
resemble in their mode of reproduction.

According to Louis Ollivier, these algae reduce the
sulphates of waters charged with sulphate of lime,
transforming them into sulphur. They even accumu-
late sulphur in their cells. When sulphur is thus

120 MICROBES, FERMENTS, AND MOULDS.

abundantly supplied to them, the microbes are very
mobile ; as soon as the quantity of sulphur diminishes
they become less mobile, and reconsume the sulphur
they have stored up; finally, they become quite
motionless — a phenomenon concomitant with the forma-
tion of spores. Within each cell of the filamentous
alga there is a minute sphere, brilliant and refracting,
of which the development is in inverse ratio to the
quantity of sulphur in the surrounding liquid. These
spores become free in the form of chaplets, after the
destruction of the cell-wall, and these chaplets are
precisely like those of Bacillus subtilis.

Planchud was the first to whom it occurred to
look for a special ferment in the glairine or baregine
which may be seen floating on the surface of sul-
phurous waters. He showed that one gramme of car-
bolic acid to a litre of water arrests the reduction of
the sulphates into sulphur, and that this reduction is
resumed as soon as the carbolic acid has evaporated.
Six grammes to the litre completely destroy the
Sulphuraria, as these algse are termed by Planchud.

This observer also performed experiments which
led him to believe that the same algae will reduce
gypsum to native sulphur, and that the vast deposits
of sulphur found in certain regions are due to the
action of this microscopic plant. It is now well
known that a chemical action of the same nature,
the production of saltpetre, is the work of similar
microbes.

MICROBES, OR BACTERIA. 121

XL THE MICROBES WHICH PRODUCE SALTPETRE.

It is known that nitre or saltpetre, i.e. potas-
sium nitrate, is produced in damp places where de-
composing animal matter is found in contact with
carbonate of potassium. It is found, combined with
other salts of lime, soda and magnesia, in stables, sheep-
folds, cellars, in the neighbourhood of urinals, and
in the earth of some localities (Peru and Chili). Its
industrial importance in the manufacture of gun-
powder, etc., has led to its collection. Formerly it
was extracted from the plaster of old houses, or from
artificial nitre works which combined conditions
favourable to its production. Nitrates are produced
by the gradual oxidation of the ammonia furnished
by animal excretions. For a long while it was supposed
that this oxidation was simply due to the influence
of porous bodies, such as earth and stone walls. Nitric
acid was produced, then nitrates of lime, potas-
sium, etc.

The researches of Boussingault, Schloesing, and
others, have now taught us that this phenomenon of
organic chemistry is due, like many others, to the
vital activity of one or more species of microbe,
whose invariable presence in the natural or artificial
nitre-works has been ascertained. These microbes are
aerobies, i.e. they only live and work when in contact
with the oxygen of the air, from which they derive

122 MICKOBES, FERMENTS, AND MOULDS.

materials for effecting oxidation. This is another
instance of the part played by microbes in artificial
fermentation.

Gayon and Dupetit believe that, in addition to
the microbes which produce nitre, there are others
which decompose the nitrates produced by the former.
When nitrate of potassium is placed in culture-
liquids, drain-water, chicken-broth, etc., it disappears
rapidly under the action of these microbes. Under
favourable conditions of temperature and environ-
ment, culture microbes daily reduce one gramme of
nitre to the litre. This decomposition causes the dis-
engagement of nitrogen, the formation of ammonia
and carbonic acid, which latter remain in solution in
the form of bicarbonate. Gayon and Dupetit believe
that this fact explains certain chemical phenomena
which occur in the soil, under the influence of manure
and water.

Thus fresh discoveries show more clearly every
day the importance of the part played by microbes
in nature. Agriculture, manufactures, geology, and
chemistry must take them into account, since they
are the active agents of a number of phenomena
which have hitherto been obscure in physics,
chemistry, and physiology.

MICROBES, OR BACTERIA. 123

XII. THE MICROBES WHICH DESTROY BUILDING
.MATERIALS.

The observations of Parize, director of the
agronomic station, Morlaix, lead to the belief that
microbes, which destroy dead bodies and effect such
various transformations in nature, not only attack
the beams of our houses, as we have already seen, but
building materials of an inorganic nature, including
stones.

On one occasion, when Parize was examining some
mucedinece which had vegetated on a brick partition,
in a closed and somewhat damp recess, he noticed
blisters on the coat of plaster. He broke one of these
blisters, and a fine red dust, consisting of pulverized
brick, issued from it. When placed in the micro-
scope, under a magnifying power of about 300
diameters, he saw, amid schistoid fragments, dia-
tomatacese and silicious algae pertaining to the original
clay of the bricks, an immense number of living
microbes : micrococcus, bacteria, amoebae, and ciliated
spores of algae, moving rapidly in the drop of water
used to moisten the dust. Some of these were in process
of budding. These organisms existed under a coat
of five to six mm. of plaster, and even of 30 mm. at
the bottom of a hole pierced by the brace ; but in this
case they were less numerous, in the proportion of
two to three. The germs and spores which exist

124 MICROBES, FEKMENTS, AND MOULDS.

both in air and water may, therefore, be indefinitely
preserved in a protective medium, such as a brick
wall covered with plaster. They are nourished at
the expense of the ammoniacal salts which are found
in the air in a gaseous state, and which are fixed by
atmospheric moisture, and it is probable that they
derive little nutriment from the solid materials in
the midst of which they live, although by their
increase disintegration may ensue. Hence, especially
from the hygienic point of view, it is so important to
disinfect the walls of hospitals, barracks, stables, etc.,
by scraping and whitewashing them.

Parize also believes that microbes may perform
a geological part in nature by disintegrating the
schistoid rocks which enter into the constitution of
arable soil. But we are now speaking of microbes of
recent origin, since the temperature to which clay is
subjected in order to make red bricks would certainly
destroy all the microbes and their germs. This is not
the case with the microbes of chalk, which, according
to Be'champ, are of very ancient origin.

XIII. THE MICROBES OF CHALK AND COAL.

Be'champ's researches tend to show that microbes,
which he calls microzyma, or small ferments, have an
almost indefinite term of life. We know that chalk
consists almost entirely of the remains of the calcareous

MICROBES, OR BACTERIA. 125

shell of Khizopoda, protozoaria or microscopic animals
which lived in incalculable numbers in the seas of the
secondary period, and which still live at the bottom
of oceans. Bechamp holds that the organic substance
of these rhizopoda, or of the microbes which live in
their midst, has retained its vitality in the mass of
chalk, since a freshly cut piece, taken from the quarry
with all possible precautions to exclude air-germs, is
able to furnish microbes which multiply rapidly in
a favourable medium, and produce various fermenta-
tions. We have already seen that bacteria germs
resist desiccation, heat, and all kinds of destructive
influences, and remain for a long while, even for
several years, in the condition of dormant spores;
but the existence of spores of the same kind in chalk
of the secondary period indicates a still more sur-
prising vitality. It is not, however, inexplicable if
we suppose that these microbes pass through
successive periods of activity and repose, and if we
compare these facts with those presented by the
microbes of saltpetre, of mineral waters, and of the
anaerobic microbes, which are able to live when
deprived of the oxygen of the air.

Bechamp was the first to observe the presence of
granulations in coal, which appear under the micro-
scope to be microbes. These microbes must be far
more ancient than those of chalk, but they have lost
all vitality ; it has been found impossible to develop
them in infusions, and to obtain fermentations from

126 MICROBES, FERMENTS, AND MOULDS.

them. But this cannot always have been* the case,
and it has been supposed that the phenomenon of
coal formations, still so obscure and so variously
explained, was, at any rate, partially due to the
physiological labour of these microbes, and con-
sequently belongs to the class of fermentations.

XIV. CHROMOGENIC MICROBES.

In addition to the colourless microbes, such as are
most of those we have hitherto considered, there are
others remarkable for their vivid and varied colours,
which betray their existence to the least practised
eyes. Many of these microbes attack our alimentary
substances, and should therefore be known to the
manufacturer and hygienist, since their action on
the human system is often injurious.

Many phenomena which have struck the imagina-
tion of ignorant and credulous people are merely due
to the presence of these coloured microbes. In 1819,
a peasant of Liguara, near Padua, was terrified by
the sight of blood-stains scattered over some polenta,
which had been made and shut up in a cupboard on
the previous evening. Next day similar patches
appeared on the bread, meat, and other articles of
food in the same cupboard. It was naturally regarded
as a miracle and warning from heaven, until the case
had been submitted to a Paduan naturalist, who easily

MICKOBES, OR BACTERIA. 127

ascertained the presence of a microscopic plant, which
Ehremberg likewise found at Berlin in analogous cir-
cumstances, and which he named Monas prodigiosa.
At that time all microbes were confounded in the
Monad genus; we now term it Micrococcus pro-
digiosus. It has been observed not only on bread,
but on the Host, on milk, paste, and on all alimentary
or farinaceous substances exposed to damp heat.

This microbe has been recently studied by Raben-
horst, who declares that it is polymorphic, and has
received a number of different names : Palmella miri-
fica, Zoogalactina imetropha, Bacterium prodigiosum,
which are only varieties of Mierococcus prodigiosus,
modified by the medium in which it is nourished.
This observer noticed its appearance on cooked meat
kept in a cellar. The spherical cells, examined under
the microscope, were shown to be filled with a reddish
oil, which gave them a peach-blossom tint, and when
transferred to raw meat they assumed a splendid
fuchsia colour, resembling spots of blood. This plant
is only developed in the dark, and the nitrogen
necessary for its nutrition must be derived from the
air, especially when it is developed on bread, the
Host, etc., in which nitrogen is deficient.

When it is said to rain blood, this phenomenon is
likewise due to the presence of a minute plant, prob-
ably similar to that which often gives a red tint to
ponds and reservoirs in autumn. This microscopic
alga appears to be the one discovered by Ehremberg in

128

MICROBES, FERMENTS, AND MOULDS.

1836, in a stream near Jena, and which he named Ophi-
domonas jenensis, or sanguined (Fig. 65). It is, on
account of its form, now placed in the genus Spirillum.
Like many other plants, it readily passes from green
to red. No one is surprised by the green scum
which covers reservoirs in summer, since it is so
common; but when this colour changes, often in a
single night, and passes from green to red, the unaccus-
tomed tint excites wonder, although it is caused by

Fig. 65. — Ophidomonas sanguined of
stagnant water (slightly magnified).

Fig. 66. — Protococcusnii'alis of
red snow (magnified).

the same plant which was green the day before. If
there is a thunderstorm or waterspout which draws
up the red water from the ponds and reservoirs, and
discharges it in the form of rain on the surrounding
country, we hear of the phenomenon that it rains blood,
and it would be easy to find in the drops of rain the
reddish microbe which imparts this colour to them.

In northern regions the snow is often tinged with
the colour of blood by an analogous Micrococcus, which

MICROBES, OE BACTERIA.

129

presents the same transition from green to red (Fig.
66). Green-tinted snow may be found adjacent to
the red snow, and under the microscope it displays
minute green globules, identical, except in colour, with
those of the red-tinted snow.

The variety of colour in these microbes is extreme.
Micrococcus aurantiacus gives an orange colour to

Fig. 67. — Bacterium cyanogenum, microbe of blue milk (Neelsen). It is probable
that several different forms are here confused under this name. £, zoogloea.

bread and eggs; M. chlorinus is grass-green ; M. cyanus
is of a beautiful azure blue ; M. violaceus is violet or
lilact and M. fulvus is rust-coloured. These have all
been observed on food. M. candidua forms little
white patches upon cheese.

The genus Bacterium also furnishes its contingent
of coloured species; such are B. xanthinum and

130 MICROBES, FERMENTS, AND MOULDS.

B. cyanogenum, which give respectively a yellow
or blue colour to milk (Fig. 67). Peasants say that
an evil eye has been cast upon the milk, but it is
easy to prove that the development of these microbes
is due to imperfect cleansing of the tin milk-vessels,
since the discolouration ceases when greater care is
taken to wash and scald the vessels.

Bread often displays microscopic growths of a
dark green or orange colour, and in this state it
cannot be introduced into the stomach without
danger. In the first case it is Bacterium cerugi-
nosum, in the second Micrococcus aurantiacus. The
badly made and badly baked bread of the French
peasants, which is often kept for a fortnight or more,
exposed to the moisture and heat which favour the
development of these microbes, sometimes displays
the first of these changes; the second is particularly
common in soldiers' bread, which must likewise be
baked several days in advance, and which is conveyed
in carts exposed to the weather. Megnin recently
observed a cryptogamic growth of this kind on the
bread distributed to the garrison of Vincennes.

The spores of these microbes are found in flour,
and resist a temperature of 120°, while they are
destroyed by that of 140°. Thus they are no longer
found in the crust, of which the temperature rises
to 200° ; but may easily subsist in the much lower
temperature of the crumb. Hence the necessity of
only using flour perfectly free from germs.

MICROBES, OR BACTERIA. 131

The pus of wounds is often coloured blue by
an aerobic micrococcus, of which the protoplasm is
colourless, but which makes a colouring matter
called pyocyanine, and this gives a blue tint to the
\int and bandages used for dressing the wound.

XV. THE MICROBE OF BALDNESS.

In addition to the numerous parasitic fungi of
skin on which the hair grows thickly, which we
have already noticed, the human hair is attacked
by a true microbe, which is, according to the re-
searches of Gruby, Malassez and Th,in, the cause of
Alopecia areata, one form of baldness. The parasite
has the appearance of a micrococcus, and penetrates
the interior of the hair, which is, as we know, hollow.
The hair must be made transparent by potash, in order
to see the microbe. It probably penetrates between
the bulb and the hair-follicle as far as the root, is
introduced into the hair, and multiplies and gradually
rises higher in it, until the substance is disorganized.
This microbe has been called Bacterium decalvans.

132 MICROBES, FERMENTS, AND MOULDS.

CHAPTER IV.

MICROBES OF THE DISEASES OF OUR DOMESTIC ANIMALS.

I. ANTHRAX, OR SPLENIC FEVEK.

THE first of the virulent and contagious diseases in
which the presence of a microbe was positively
ascertained was anthrax, or splenic fever, which
attacks most of our horned animals, and especially
cattle and sheep.

As early as 1850, Davaine had observed the
presence of minute rods in the blood of animals which
died of splenic fever; but it was only in 1863, after
Pasteur's first researches into the part played by
microbes in fermentations, that Davaine suspected
these rods of being the actual cause of the disease.
He inoculated healthy animals with the tainted blood,
and thus ascertained that even a very minute dose
would produce a fatal attack of the disease, and the
rods, to which he gave the name of Bacteridia, could
always be discovered in enormous numbers in the
blood.

ANTHRAX. 133

The microbe so named by Davaine must from its
characteristics be assigned to the genus Bacillus, and
is now termed Bacillus anthracis. This disease,
which affects men as well as animals, is characterized
by general depression, by redness and congestion of
the eyes, by short and irregular respiration, and by
the formation of abscesses, which feature, in the case
of the human subject, has procured for it the name of
malignant pustule. The disease is quickly terminated

Fig. 68.— Bacillus anthracis of splenic fever in different stages of development:
bacilli, spores, and curled filaments (much enlarged).

by death, and an autopsy shows that the blood is
black, that intestinal haemorrhage has occurred, and
that the spleen is abnormally large, heavy, and gorged
with blood ; hence the name of splenic fever. The
disease is generally inoculated by the bite of flies
which have settled upon carcases and absorbed the
bacteria, or by blood-poisoning through some accidental
scratch, and this is especially the case with knackers

134 MICKOBES, FERMENTS, AND MOULDS.

and butchers who break and handle the bones of
animals which have died of anthrax.

The period of incubation is very short. An ox
which has been at work may return to the stall
apparently healthy. He eats as usual ; then lies down
on his side and breathes heavily, while the eyes are
still clear. Suddenly his head drops, his body grows
cold ; at the end of an hour the eye becomes glazed ;
the animal struggles to get up, and falls dead. In
this case, the illness has only lasted for an hour and
a half (Empis).

Fie. 69. — Bacillus anthracis, produced in guinea-pig by inoculation: corpuscles of
blood and bacilli.

In order to prove that the disease is really caused
by Bacillus anthracis, Pasteur inserted a very small
drop of blood, taken from an animal which had
recently died of anthrax, in a glass flask which con-
tained an infusion of yeast, neutralized by potassium
and previously sterilized. In twenty-four hours the
liquid, which had been clear, was seen to be full of
very light flakes, produced by masses of bacilli, readily

ANTHRAX. 135

discernible under the microscope. A drop from the
first flask produced the same effect in a second, and
from that to a third, and so on. By this means the
organism was completely freed from all which was
foreign to it in the original blood, since it is calculated
that after from eight to ten of such processes, the
drop of blood was diluted in a volume of liquid
greater than the volume of the earth. Yet the tenth,
twentieth, and even the fiftieth infusion would, when
a drop was inserted under the skin of a sheep, procure
its death by splenic fever, with the same symptoms
as those produced by the original drop of blood. The
bacillus is, therefore, the sole cause of the disease.

These cultures have often since been repeated by
numerous observers, so that the microbe has been
studied in all its forms, and the extent of its poly-
morphism has been ascertained. At the end of two
days the bacterium, which, while still in the blood,
is of a short, abrupt form, displays excessively long
filaments, which are sometimes rolled up like a coil
of string. In about a week many of the filaments
contain refracting, somewhat elongated nuclei. These
nuclei presently f6rm chaplets, in consequence of the
rupture of the cell- wall of the rod which gave birth
to them ; others, again, float in the liquid in the form
of isolated globules. These nuclei are the spores or
germs of the microbes, which germinate when placed
in the infusion, become elongated, and reproduce fresh
bacilli.

136 MICROBES, FERMENTS, AND MOULDS.

These spores are much more tenacious of life than
the microbes themselves. The latter perish in a tempe-
rature of 60°, by desiccation, in a vacuum, in carbonic
acid, alcohol, and compressed oxygen. The spores
on the other hand, resist desiccation, so that they can
float in the air in the form of dust. They also resist
a temperature of from 90° to 95°, and the effects of a
vacuum, of carbonic acid, of alcohol, and compressed
oxygen.

In 1873, Pasteur, aided by Chamberland and Roux,
carried on some experiments on a farm near Chartres,
in order to discover why this disease is so common in
some districts, in which its spread cannot be ascribed
to the bite of flies. Grass, on which the germs of
bacteridia had been placed, was given to the sheep.
A certain number of them died of splenic fever. The
glands and tissues of the back of the throat were
very much swelled, as if the inoculation had occurred
in the upper part of the alimentary canal, and by
means of slight wounds on the surface of the mucous
membrane of the mouth. In order to verify the fact,
the grass given to the sheep was mixed with thistles
and bearded ears of wheat and barley, or other prickly
matter, and in consequence the mortality was sensibly
increased.

In cases of spontaneous disease it was surmised
that the germs which were artificially introduced into
food in the course of these experiments, are found
upon the grass, especially in the neighbourhood of

ANTHRAX. 137

places in which infected animals had been buried. It
was, in fact, ascertained that these germs existed
above and around the infected carcases, and that they
were absent at a certain distance from their burial-
place. It is true that putrid fermentation destroys
most of the bacteria, but before this occurs a certain
number of microbes are dispersed by the gas dis-
engaged from the carcase ; these dry up and produce
germs, which retain their vitality in the soil for a
long while.

The mechanism by means of which these germs
are brought to the surface of the soil and on to the
grass on which the sheep feed is at once simple and
remarkable. Earth-worms prefer soils which are rich
in humus or decomposing organic substance, and seek
their food round the carcase. They swallow the earth
containing the germs of which we have spoken, which
they deposit on the surface of the soil, after it has
traversed their intestinal canals, in the little heaps
with which we are all acquainted. The germs do not
lose their virulence in their passage through the
worms' intestines, and if the sheep swallow them
together with the grass on which they browse, they
may contract the disease. The turning-up of the soil
by the spade or plough may produce the same effect.'

A certain warmth is necessary for the formation
of germs; none are produced when it falls below 12°,
and the carcases buried in winter aje therefore less
dangerous than those buried in the spring and sum-

138 MICROBES, FERMENTS, AND MOULDS.

mer. It is, in fact, in hot weather that the disease
is most prevalent. Animals may, however, contract
it even in their stalls from eating dry fodder on which
germs of these bacteria remain.

Pasteur and his pupils performed an experiment
in the Jura in 1879, which clearly shows that the
presence of germs above the trenches in which car-
cases have been buried is the principal cause of
inoculation. Twenty oxen or cows had perished, and
several of them were buried in trenches in a meadow
where the presence of these germs was ascertained.
Three of the graves were, surrounded by a fence,
within which four sheep were placed. Other sheep
were folded within a few yards of the former, but in
places where no infected animals had been buried.
At the end of three days, three of the sheep folded
above the graves had died of splenic fever, while those
excluded from them continued to be healthy. This
result speaks for itself.

Malignant pustule, which is simply splenic fever,
affects shepherds, butchers, and tanners, who handle
the flesh and hide of tainted animals. Inoculation
with the bacillus almost always occurs in consequence
of a wound or scratch on the hands or face. In Ger-
many, fatal cases of anthrax have been observed, in
which the disease has been introduced through the
mouth or lungs, as in the case of the sheep observed
by Pasteur. The human subject appears, however,
.to be less apt to contract the disease than herbivora,

ANTHRAX. 139

since the flesh of animals affected by splenic fever,
and only killed when the microbe is fully developed
in the blood, is often eaten in farmhouses. In this
case the custom prevalent among French peasants of
eating over-cooked meat constitutes the chief safeguard,
since the bacteria and their germs are thus destroyed.

II. VACCINATION FOE ANTHRAX.

The rapidity with which anthrax is propagated
by inoculation generally renders all kinds of treat-
ment useless; if, however, the wound through which
the microbe is introduced can be discovered, it should
be cauterized at once. This method is often successful
in man. The pustule is cauterized with red-hot iron,
or with bichloride of mercury and thymic acid, two
powerful antiseptics, certain to destroy the bacteridium.
It is expedient, as an hygienic measure, to burn the
tainted carcases, and if this is not done, they should
be buried at a much greater depth than is usually the
case.

But the preservative means on which chief re-
liance is now placed is vaccination with the virus
of anthrax. Pasteur has ascertained that when
animals are inoculated with a liquid containing bac-
teridia of which the virulence has been attenuated
by culture carried as far as the tenth generation, or
even further, their lives are preserved. They take

140 MICROBES, FERMENTS, AND MOULDS.

the disease, but generally in a very mild form, and it
is an important result of this treatment that they are
henceforward safe from a fresh attack of the disease ;
in a word, they are vaccinated against anthrax.

In the cultures prepared with the view of attenu-
ating the microbe, it is the action of the oxygen of
the air which renders the bacteridium less virulent.
It should be subjected to a temperature of from 42°
to 43° in the case of Bacillus anthracis, to enable it
to multiply, and at the same time to check the pro-
duction of spores which might make the liquid too
powerful. At the end of the week, the culture, which
at first killed the whole of ten sheep, killed only four
or five out of ten. In ten or twelve days it ceased
to kill any ; the disease was perfectly mild, as in the
case of the human vaccinia, of which we shall speak
presently. After the bacteridia have been attenuated,
they can be cultivated in the lower temperature of
from 30° to 35°, and only produce spores of the same
attenuated strength as the filaments which form them
(Chamberland).

The vaccine thus obtained in Pasteur's laboratory
is now distributed throughout the world, and has
already saved numerous flocks from almost certain
destruction. Although this process has only been
known for a few years, its results are such that the
gain to agriculture already amounts to many thousands
of pounds.

Toussaint makes use of a slightly different mode

ANTHRAX. 141

of preparing a vaccine virus, which is, however,
analogous to that of Pasteur. He subjects the lymph
of the blood of a diseased animal to a temperature
of 50°, and thus transforms it into vaccine. Toussaint
considers the high temperature to be the principal
agent of attenuation, and ascribes little or no im-
portance to the action of the oxygen in the air.

Chamberland and Roux have recently made re-
searches with the object of obtaining a similar
vaccine by attenuating the primitive virus by means
of antiseptic substances. They have ascertained that
a solution of carbolic acid of one part in six hundred
destroys the microbes of anthrax, while they can live
and flourish in a solution of one part in nine hundred,
but without producing spores, and their virulence is
attenuated. When a nourishing broth is added to
a solution of one in six hundred, the microbe can live
and grow in it for months. Since the chief condition
of attenuation consists in the absence of spores, this
condition seems to be realized by the culture in a
solution of carbolic acid, one in nine hundred, and it
is probable that a fresh form of attenuated virus
may thus be obtained. Diluted sulphuric acid gives
analogous results.

However this may be, the vaccine prepared by
Pasteur's process is the only one which has been
largely used, and which has afforded certain results to
cattle-breeders.

Public experiments, performed before commis-

142 MICROBES, FERMENTS, AND MOULDS.

sions composed of most competent men, have clearly
shown the virtue of the protective action. In the
summer of 1881, the initiation was taken by the
Melun Society of Agriculture. Twenty-five sheep and
eight cows or oxen were vaccinated at Pouilly-le-Fort,
and then re-inoculated with blood from animals which
had recently died of anthrax, together with twenty-
five sheep and five cows which had not been previously
vaccinated. None of the vaccinated animals suffered
while the twenty-five test sheep died within forty-
eight hours, and the five cows were so ill that the
veterinary surgeons despaired of them for several
days.

This experiment was publicly repeated in Sep-
tember, 1881, by Thuillier, Pasteur's fellow- worker,
whose death we have recently had to deplore, before the
representatives of the Austro-Hungarian Government ;
and again near Berlin, in 1882, before the representa-
tives of the German Government, and always with
the same success. Up to April, 1882, more than
130,000 sheep and 2000 oxen or cows had been vac-
cinated ; and since that time the demand for vaccine
from Pasteur's laboratory has reached him from every
quarter.

III. FOWL CHOLERA.

The sickness of barn-door poultry, which is com-
monly called cholera, is caused by the presence in the

OTHER DISEASES OP DOMESTIC ANIMALS. 143

blood of a small micrococcus or bacterium in the form
of the figure 8, differing, therefore, in form from Bacil-
lus anthracis, but also an aerobie. It may be cultivated
in chicken-broth, neutralized by potash, while it soon
dies in the extract of yeast, which is so well adapted
to Bacillus anthracis.

The microbe of this disease may also be attenuated
by culture, and it may be done more easily than in
the case of anthrax, since it is not necessary to raise
the temperature, as the bacterium of fowl-cholera does
not produce spores under culture. Pasteur has there-
fore been able to prepare an attenuated virus well
adapted to protect fowls from further attacks of this
disease.

IV. SWINE FEVER.

The disease affecting swine, which is called rouget,
or swine fever, in the south of France, has been
recently studied by Detmers in the United States,
where it is also very prevalent, and by Pasteur in
the department of Vaucluse. It is a kind of pneumo-
enteritis.

These observers consider that the disease is caused
by a very slender microbe, formed, like that of fowl-
cholera, in the shape of the figure 8, but more minute.
Others say that there is a bacillus which was observed
by Klein as early as 1878 in swine attacked by this
disease. In spite of the apparent contradiction, it is

144 MICROBES, FERMENTS, AND MOULDS.

probable that we have only two forms of the same
microbe, for the bacillus in Klein's culture at first
resembles Bacterium termo, in the form of an 8, before
it is elongated into rods.

Pasteur has succeeded in making cultures of
microbes in the figure 8. He has inoculated swine
with the attenuated form, after which they have been

Fig. 70.— Swine fever: section of a lymphatic gland, showing a blood-vessel filled with
microbes (much enlarged : Klein).

able to resist the disease, so there is reason to hope
that in the near future this new vaccine, containing
the attenuated microbe, may become the safeguard of
our pig-sties.

V. OF SOME OTHER DISEASES PECULIAR TO DOMESTIC
ANIMALS.

An epidemic which raged in Paris in 1881 was
called the typhoid fever of horses, and was fatal to
more than 1500 animals belonging to the General Om-
nibus Company in that city. This disease is also pro-

OTHEE DISEASES OF DOMESTIC ANIMALS. 14fj

duced by a microbe, with which Pasteur was able to
inoculate other animals (rabbits) ; for this purpose
he made use of the serous discharge from the horses'
nostrils. The inoculated rabbits died with all the
symptoms and lesions characteristic of the disease.

The attenuation of this microbe by culture is
difficult, since at the end of a certain time the action
of the air kills it. Pasteur has, however, found an
expedient by which to accomplish his purpose. When
the culture is shown to be sterile in consequence of
the death of the microbe, he takes as the mother
culture of a fresh series of daily cultures the one which
was made on the day preceding the death of the first
mother culture. In this way he has obtained an
attenuated virus with which to inoculate rabbits, and
the same result might undoubtedly be obtained in
the case of horses.

There are many other contagious diseases which
affect domestic animals, and which are probably due to
microbes, such as, for instance, the infectious pneumonia
of horned cattle. This was probably the first disease in
which the protective effects of inoculation were tried
according to Wilhelm's method. This method consisted
in making an incision under the animal's tail with a
scalpel dipped in the purulent mucus or blood taken
from the lung of a beast which had died of pneumonia ;
sometimes the serous discharge from the swelling under
the tail of an inoculated animal was used for others.
Fever and loss of appetite ensued, lasting from eight

146 MICKOBES, FERMENTS, AND MOULDS.

to twenty-five days, but the animal was afterwards
safe from further attacks of the disease.

Cattle plague, or contagious typhus, is likewise
ascribed to the presence of a microbe with which we
are as yet imperfectly acquainted.

Experimental septicemia is entitled to special men-
tion, since it has too often been confounded with
anthrax, and has been unskilfully produced with the
intention of vaccinating animals in accordance with
Pasteur's process. This occurs when too long an
interval (twenty-four hours) elapses after the death of

Fig. 71.— Septic vibrio, bacillus of malignant oedema (Koch) : a, taken from spleen of
guinea-pig ; b, from a mouse's lung.

an animal, before taking from it the blood intended for
vaccine cultures. After this date the blood no longer
contains Bacillus anthracis, which is succeeded by
another microbe termed Vibrio septicus, differing
widely from the anthrax microbe in form, habit, and
character (Fig. 71). Bacillus anthracis is straight and
immobile, while the septic vibrio is sinuous, curled,
and mobile. Moreover, it is anaerobic, and does not
survive contact with the air, but it thrives in a vacuum
or in carbonic acid. Since Bacillus anthracis is, on

OTHEE DISEASES OF DOMESTIC ANIMALS. 147

the other hand, an aerobie, it is clear that the two
microbes cannot exist simultaneously in the blood or
in the same culture liquid.

The inoculation with this fresh microbe is no less
fatal; its action is even more rapid than that of
Bacillus anthracis, but the lesions are not the same; the
spleen remains normal, while the liver is discoloured.

The septic vibrio is only found in minute quantities
in the blood, so that it has escaped the notice of many
observers. It is, however, found in immense numbers
in the muscles, in the serous fluid of the intestines, and
of other organs. It is very common in the intestines,
and is probably the beginning of putrefaction.

VI. RABIES.

Rabies is a canine disease which is communicated
by a bite, and the inoculation of man and other
animals by the saliva. We are not yet precisely
acquainted with the microbe which causes the disease,
but Pasteur's recent researches have thrown consider-
able light on its life-history, which is still, however,
too much involved in obscurity.

It must first be observed that the hypothetical
microbe of rabies, which no one has yet discovered,
should not be confounded with the microbe of human
saliva ; this is found in the mouths of healthy persons,
and will be briefly discussed in the following chapter.

148 MICROBES, FERMENTS, AND MOULDS.

The following conclusions are the result of Pasteur's
researches into the virus of rabies.

This virus is found in the saliva of animals and men
affected by rabies, associated with various microbes.
Inoculation with the saliva may produce death in three
forms: by the salivary microbe, by the excessive
development of pus, and finally by rabies.

The brain, and especially the medulla oblongata, of
men and animals which have died of rabies, is always
virulent until putrefaction has set in. So also is
the spinal cord. The virus is, therefore, essentially
localized in the nervous system.

Rabies is rapidly and certainly developed by tre-
phining the bones of the cranium, and then inocu-
lating the surface of the brain with the blood or saliva
of a rabid animal. In this way there is a suppression
of the long incubation which ensues from simple
inoculation of the blood by a bite or intra-venous
injection on any part of the body. It is probable that
in this case the spinal cord is the first to be affected
by the virus introduced into the blood ; it then fastens
on its tissues and multiplies in them.

As a general rule, a first attack which has not proved
fatal is no protection against a fresh attack. In 1881,
however, a dog which had displayed the first symptoms
of the disease of which the other animals associated
with him had died, not only recovered, but failed to
take rabies by trephining, when re-inoculated in 1882.
Pasteur is now in possession of four dogs which are

OTHER DISEASES OF DOMESTIC ANIMALS. 149

absolutely secured from infection, whatever be the mode
of inoculation, and the intensity of the virus. All the
other test dogs which were inoculated at the same
time died of rabies. In 1884, Pasteur found the means
of attenuating the virus. For this purpose he has
inoculated a morsel of the brain of a mad dog into a
rabbit's brain, and has passed the virus proceeding
from the rabbit through the organism of a monkey,
whence it becomes attenuated and a protective vaccine
for dogs. This is the first step towards the extinction
of this terrible disease.

VII. GLANDERS.

This, again, is a disease easily transmitted from
horses to man. Glanders, or farcy, is caused by the
presence of a bacterium, observed as early as 1868
by Christot and Kiener, and more recently studied at
Berlin by Schiitz and Lofler. This microbe appears
in the form of very fine rods (bacillus) in the lungs,
liver, spleen, and nasal cavity. Babes and Ilavas
found this bacillus in the human subject in 1881.
Experimental cultures have been made simultaneously
in France and Germany, and have given identical
results. , -

Bouchard, Capitan, and Charrin made their cultures
in neutralized solutions of extract of meat, maintained
at a temperature of 37°. By means of successive
sowings, they have obtained the production of un-

150 MICROBES, FERMENTS, AND MOULDS.

mixed microbes, presenting no trace of the original
liquid, and this was done in vessels protected from air-
germs. These cultures may be carried to the eighth
generation.

Asses and horses inoculated with liquid containing
the microbes produced by this culture have died with
the lesions characteristic of glanders (glanderous
tubercles in the spleen, lungs, etc.). Cats and other
animals which have been inoculated in the same way
die with glanderous tubercles in the lymphatic glands
and other organs.

It follows from these experiments that the microbe
which causes this disease is always reproduced in the
different culture liquids with its characteristic form
and dimensions ; that uni-ungulates can be inoculated
with it, as well as man and other animals. In fact, this
microbe is the essential cause of the disease.

VIII. PEBRINE AND FLACHEEIE, DISEASES AFFECTING
SILKWORMS.

"We have already spoken of muscardine, a silk-
worm's disease produced by a microscopic fungus;
two other diseases are caused by distinct microbes, of
which we must shortly speak.

Pebrine. — In the silkworm nurseries, in which this
disease prevails, the silkworms which issue from the
eggs, technically called seed, are slowly and irregularly
developed, so as to vary greatly in size. Many die

OTHER DISEASES OF DOMESTIC ANIMALS. 151

young, and those which survive the fourth moult
shrink and shrivel away ; they can hardly creep on to
the heather to spin their cocoon, and produce scarcely
any silk.

On an examination of the worms which have died
of this disease, De Quatrefages ascertained the presence
of minute stains on the skin and in the interior of
the body, which he compared to a sprinkling of
black pepper; hence the name pebrine. Under the
microscope these stains assume the form of small
mobile granules like bacteria, which Cornalia termed
vibratile corpuscles, on account of their movements.
Finally, Osimo and Vittadini ascertained the existence
of these corpuscles in the eggs, and consequently
showed that the epidemic might be averted by the
sole use of healthy eggs, of which the soundness
should be established by microscopic examination.

It was at about this date, 1865, that Pasteur under-
took the exhaustive study of pebrine ; but Be'champ
was the first to pronounce the disease parasitic,
resembling muscardine in this respect, and caused by
the attacks of a microbe — or microzyma, to adopt
Bechamp's name — of which the germ or spore is derived
from the air, at first attacking the silkworm from
without, but multiplying in its interior, and developing
with its growth, so that the infected moth is unable
to lay its eggs without depositing the spores of the
microbe at the same time, and thus exposing the
young grub to attack as soon as it is born. Pasteur's

152 MICKOBES, FERMENTS, AND MOULDS.

own researches soon induced him to adopt the
same view.

The pebrine microbe was long regarded as a true
bacterium, successively described as Bacterium bom-
bycis, Nosema bombycis (Fig. 72), and
Panistophyton ovate. Balbiani's recent
r\* 0^0 ^ researches tend to show that it should
°°0 o 9- be assigned to another group, much
0-( nearer to animals, and designated

Fig. 72. — Nosema,
bombycis, pebrine

microbe (x 500 SpOTozoaria. — These protista, still
regarded as plants by many naturalists,
chiefly differ from bacteria by their mode of growth
and reproduction, in which they resemble the para-
sitic protozoaria, termed Psorospermia, Coccidies, and
Gregarinidce.

In Sporozoaria, growth by fission, the rule in all
bacteria, has not been observed ; this distinction is
fundamental. Sporozoaria multiply by free spore-
formation in a mass of sarcode substance (protoplasm),
resulting from the encysting of the primitive corpuscles
(mother-cells). The formation of numerous spores
may be observed within the mother-cells, having the
appearance of pseudonavicellce or spores of gregari-
nidseand psorospermia (parasites of vertebrate animals).
Balbiani forms these organisms, which are found in
many insects, into a small group, which he terms
JMicrosporidia.

The ripe spores are the vibratile corpuscles of

OTHEE DISEASES OF DOMESTIC ANIMALS. 153

Cornalia. They closely resemble the spores of some
bacilli (B. amylobacter, for instance), and their germi-
nation is likewise effected by perforation of the spore
at one end, and issue of the protoplasm from the
interior. This, however, does not issue in a rod-like
form (Bacillus), but in that of a small protoplasmic
mass, with amoeboid movements, a characteristic not
observed in any bacterium (Balbiani).

The other species of silkworms which have been
recently introduced, notably the oak silkworm from
China (Attacus Pernyi),&£Q attacked by microsporidia
analogous to those of pebrine.

Pasteur has indicated the mode of averting the
ravages of this disease. He has thus addressed the
breeders: "If you wish to know whether a lot of
cocoons will yield good seed, separate a portion of them
and subject them to heat, which will accelerate the
escape of the moth by four or five days, and examine
them under the microscope to ascertain whether cor-
puscles of pebrine are present. If they are, send all the
cocoons to the silk factory. If they are not diseased,
allow them to breed, and the seed will be good and
will hatch out successfully. In a word, start with
absolutely healthy seed, produced by absolutely pure
parents, and rear them under such conditions of
cleanliness and isolation as may ensure immunity
from infection."

When the disease is developed, fumigation with
sulphurous acid is recommended, or preferably with

154 MICROBES, FERMENTS, AND MOULDS.

creosote or carbolic acid, which do not affect the silk-
worms (Bechamp), and which hinder the development
of microsporidia. These fumigations likewise keep
the litter from becoming corrupt, and in a properly
conducted nursery the litter is kept dry.

Flacherie. — Wrongly confounded with pebrine, the
disease flacherie is still more destructive to silkworms.
The symptoms are remarkable. The rearing of silk-
worms often goes on regularly up to the fourth moult,
and success seems assured, when the silkworms suddenly
cease to feed, avoid the leaves, become torpid, and
perish, while still retaining an appearance of vitality,
so that it is necessary to touch them in order to ascer-
tain that they are dead. In this state they are termed
marts-flats. A few days, sometimes even a few hours,
suffice to transform the most flourishing nursery into
a charnel-house.

Pasteur examined these morts-flats, and found that
the leaves contained in the stomach and intestine were
full of bacteria, resembling those which are developed
when the leaves are bruised in
a glass of water and left to putrefy
<* (Fig. 73). In a healthy specimen,

of good digestion, these bacteria

are never found' li is therefore
evident that the disease is owing
to bad digestion, and becomes rapidly fatal in animals
which consume an enormous amount of food, and do
nothing but eat from morning to night. The digestive

OTHER DISEASES OF DOMESTIC ANIMALS. 155

ferments of unhealthy silkworms do not suffice to
destroy the bacteria of the leaves, nor to neutralize
their injurious effects.

These bacteria are really the cause of the disease,
for if even a minute quantity of the leaves taken from
the intestine of diseased silkworms be given to healthy
specimens, they soon die of the same disease. It is,
therefore, essentially contagious, and in order to prevent
the diseased silkworms from contaminating the healthy
by soiling the leaves on which the latter are about to
feed, as much space should be assigned to them as
possible.

Good seed should also be selected, since it has been
ascertained that some lots of seed are more liable to
the disease than others. The affection does not indeed
begin in the egg, as in pebrine, but the question of
heredity comes in. It is clear that when a silkworm
has been affected by flacherie without dying of it, its
eggs will have little vitality, and the grubs which issue
from them will be predisposed by their feeble constitu-
tion to contract the disease.

156 MICROBES, FERMENTS, AND MOULDS.

CHAPTER Y.

THE MICROBES OF HUMAN DISEASES.

I. MICROBES OF AIR, EARTH, AND WATER.

IT is generally admitted that the large majority of
epidemic and contagious diseases which affect men
and animals are caused by the introduction of certain
kinds of microbes into the organism. In reply to the
question how these microbes are introduced into the
body, and where they are before entering it, it is easy
to show that these microbes exist in immense numbers
— they or their spores — in the air we breathe, in the
water we drink, in the ground on which we tread,
and whence there rises, whenever it is dry, a fine dust
charged with all sorts of germs, which penetrate
together with the air into our mouths and lungs.

For a long while we were almost completely
ignorant of the conditions of existence of these
microbes when they are in the soil or water. The
recent researches of Zopf, a German botanist, tend to
show that among the inferior algse termed Bacteria

THE MICROBES OF HUMAN DISEASES. 157

or Schizophyta, there is a very remarkable dimorphism
of mode and habitat. In Beggiatoa of sulphurous
waters, for instance, and in Cladothrix, which forms a
whitish pellicle on the surface of putrefying liquids,
Zopf has found, under certain conditions, all the forms
designated as Micrococcus, Bacillus, Leptothrix, and
Bacterium; that is, microbes strictly so called, in-
cluding those which are the producing agents of
contagious diseases.

Where these algae are found in water or on a damp
soil, conditions of existence favourable to their develop-
ment, there they live and multiply. But when the
soil dries up, when a river returns to its bed after
a flood, or a marsh disappears in consequence of the
evaporation of its waters, all these algae give forth
dormant spores, destined to ensure their propagation.
We have described the formation of these spores by
concentration of the protoplasm in the interior of
each cell ; in this form their volume is very small, and
they are extremely light, so that as soon as they are
desiccated, and then only, these spores are carried
away by the slightest breeze and borne to great dis-
tances. These are termed air-germs.

When these moving germs encounter a favourable
medium, at once moist and warm, such as the human
mouth or lungs, they fasten there and are immediately
developed, first in the form of Micrococcws, then of
that of Bacterium, Bacillus, or Leptothrix, according
to the species to which the spore in question belongs.

158 MICROBES, FERMENTS, AND MOULDS.

Schizophyta may therefore have two very different
modes of existence, comparable to the hetersecia (change
of habitat) and dimorphism of the fungi Ascomycetes
and Basidiomycetes. Schizomycetes however, although,
like fungi, they obtain their nourishment from organic
substances which have been already elaborated, are
not true parasites in the first stage of their existence,
during which stage they live freely in the water, or on
the damp soil. They become true parasites when they
penetrate into the blood and tissues of man, in which
they necessarily live at the expense of their host.

Hence it may be seen why half-dried marshes,
meadows from which a river has retreated in order
to return to its bed, great excavations of the soil
necessary in railway -cuttings, etc., become the source
of a large number of epidemic or contagious diseases.
In all these places the subsiding waters have left
Schizophyta, or microbes in a dried state, and these
are soon transformed into dormant spores, which are
diffused through the air and enter the mouth and
lungs of men living near the rivers and marshes, or
who are working on the railway-cutting. The soil
which has remained undisturbed for a long while is
full of dormant spores, drawn into it by the rain to
a greater or less depth; these may preserve their
vitality for many years, waiting for the favourable
medium which leads to their fresh development.

An acquaintance with air-germs, with the microbes
of earth and water, has therefore become indispensable

THE MICKOBES OF HUMAN DISEASES. 159

to the physician and to the professor of hygiene, who
are anxious to decide on the precise cause of great
epidemics in order, if possible, to foresee and avert
them. This new branch of meteorology has been
termed atmospheric micrography, since it necessarily
involves the use of the microscope.

The Microbes of the Atmosphere. — In the observa-
tory of Montsouris, Paris, there is now a special
laboratory under the direction of Miquel, with the
object of studying the living organisms of the air,
of establishing statistics of their times and seasons,

Figs. 74, 75.— Microbes and spores of atmospheric dust, mixed with amorphous
particles, and collected by the aeroscope.

and of drawing general conclusions as to the hygienic
condition of the air, according as it is more or
less charged with the microbes and spores which
are factors of disease. This laboratory is provided
with the apparatus necessary for such kinds of
research.

The first of these apparatus serves to collect the
living organisms which are always mingled with a
large amount of inert dust (Figs. 74, 75). The

160 MICROBES, FERMENTS, AND MOULDS.

apparatus is founded on the principle of the aeroscope,
invented by Pouchet for the examination of air-dust.
It consists of a small cylinder in which a current of
air is produced by means of an aspirator, on which
running water acts, similar to those in use in all
laboratories of physics and chemistry. A thin plate of
glass, which has on it a layer of glycerine, is placed
at the bottom of the cylinder, so as to intercept the
current of air and arrest the dust. The apparatus
employed by Miquel at Montsouris is only a modifica-
tion and improvement of the one devised by Pouchet.
The glass slide is then transferred to the objective
of the microscope in order that the dust deposited
on it may be examined.

This process has enabled Miquel to define the laws
which rule the appearance of microbes in the atmo-
sphere, and he has been able to calculate their number
in a given volume of air. With respect to such fungi
and algae as live in our houses (moulds), and on our
roofs, walls, and on damp ground (such algae as Peni-
cillium, Protococcus, Chlorococcus, etc.), he has arrived
at the following results, as far as Montsouris, the site
of his experiments, is concerned.

Few in number in January and February, the
number of mould-spores further diminishes in March,
and rises again in April, May, and June, in which
month the maximum is attained. The decrease is slow
up to October, more marked in November, and the
minimum is observed in December. In this case the

THE MICKOBES OP HUMAN DISEASES. 161

influence of rain and damp is very marked. In winter
the average number of spores in every cubic metre of
air does not exceed 7000, while in June it rises to
35,000.

In summer, however, when the temperature is
very high, the number of spores is not great ; for this
reason, that, in spite of the heat, the air is moist, and
the spores settle on the ground, plants, or other objects,
instead of floating in the air. On the other hand, in
winter, since very cold weather is generally dry, the
number of air-germs increases.

In summer, storms only purify the air for a very
short time ; within fifteen or eighteen hours after the
rain, the germs reappear, and are five to ten times
more numerous than before. It seems that storms
give an energetic impulse to the production of moulds.

If we turn to consider microbes, strictly so called,
or the bacteria which are the causes of malignant
diseases, research becomes more difficult, on account
of their smaller size and great transparency. An
expedient is necessary to reveal their presence and
enable us to count them accurately: this expedient
consists in staining them by various processes, of
which we shall speak when we come to discuss the
micrographic study of drinking-water. Miquel prefers
the process of filtration of the air invented by
Pasteur, which consists in passing the air and aqueous
vapour into such sterilized liquids as are favourable
to the nutrition of microbes.

162 MICROBES, FERMENTS, AND MOULDS.

Sterilized Flasks. — Pasteur has shown that air may
be deprived of all its germs by being passed through
a capillary tube, turned back upon itself. He takes
a glass flask and draws out its neck so as to form
a long tube, which is bent in different directions
(Fig. 76). The prolonged application of heat expels
the. air contained in the flask, which is therefore
sterilized, and it is then allowed to cool slowly. A

Fig. 76.— Pasteur's flask, with bent tube, containing a culture liquid, sterilized.

hot culture liquid may now be put into the flask. It
must be ascertained, by keeping the flask at a tem-
perature of 36° for several days, that the liquid is
completely sterilized. The culture flasks are thus
fitted to receive the air which is to be the object of
study, together with the spores contained in it.

Culture liquids.^There is a considerable variety
of culture liquids : Pasteur's mineral solution, infusion
of hay or turnips, neutral urine, chicken-broth, beef-
tea, etc. They should be plunged in a bath heated
to a temperature of 150° to 180°, since some spores

THE MICROBES OF HUMAN DISEASES. 163

are capable of resisting a prolonged boiling at a
temperature of 100° ; they still live and are capable
of germinating and multiplying when the liquid is
cooled.

Culture liquids may also be sterilized without
the use of heat, which to some extent affects their
nature, by filtering them through a porous substance —
biscuit- ware, or a mixture of plaster and amianthus,
etc. A more perfect apparatus is employed by Miquel,
consisting of a filter of very thick paper, through
which the liquid is forced by the simultaneous action
of a vacuum on one side, and of strong pressure on
the other.

For the artificial culture of microbes, solid or
partially solid substances are by preference often used,
such as gelatine, or slices of potatoes, carrots, hard
eggs, etc., prepared in different ways and sterilized
before use. We cannot here describe in detail all the
processes employed and the precautions necessary in
order to avoid error. We must content ourselves with
giving the results obtained by Miquel.

There are on an average 80 bacteria in a cubic
metre of Montsouris air. A hundred of these bacteria
includes 66 Micrococci, 21 Bacteria and 13 Bacilli.
In rain water there is a different proportion : 28
Micrococci, 9 Bacteria, 63 Bacilli. At the beginning
of a thunderstorm, the rain-water includes a consider-
able number, about 15 to the cubic centimetre ; then
the number diminishes, but Miquel states that " after

164 MICROBES, FERMENTS, AND MOULDS.

two or three days of damp, rainy weather, the rain-
water often contains more bacteria than when it began
to fall. Since the atmosphere is then excessively pure,
it seems that the bacteria are able to live and
multiply in the clouds, or else that the clouds, in
their passage through space, take up a varying con-
tingent of germs."

The maximum of air-germs is observed in autumn,
the minimum in winter; thus, 50 bacteria were counted
in December and January, only 33 in February, 105
in May, 50 in June, and 170 in October.

Inversely to what occurs with moulds, the number
of bacteria, low in rainy weather, rises when all
moisture has disappeared from the surface of the soil.
The effect of dryness is greater than that of warmth.
This explains the scarcity of bacteria after the great
rains of February, April, and June. A long drought
is, however, unfavourable to their development.

Miquel's experiments lead him to conclude that
dew, the evaporation from the soil, is never charged
with spores. The dry dust in the neighbourhood of
inhabited places, and especially of hospitals, is, on the
other hand, charged with microbes. In the centre of
Paris, for example, in the Rue de Rivoli, there are
nine or ten times as many microbes in the atmosphere
as in the neighbourhood of the fortifications. In the
Montsouris Observatory, south of Paris, the north
winds bring many more bacteria than the south winds.
The most impure wind comes from the hills of Villette

THE MICROBES OF HUMAN DISEASES. 165

and Belleville, crowded and populous quarters, in which
are also cemeteries and slaughter-houses.

It has long been established that the air is much
purer on high mountains or on the sea, than in plains
and in the vicinity of inhabited places. If glass flasks
which have been previously sterilized and deprived
of air are taken to a great height on the Alps or
Pyrenees, and. then filled with air, it will be difficult
to detect any microbes, and the few which may be
found are possibly brought by the observer. So
again, on the top of the Pantheon, a cubic metre of
air only contains 28 microbes, while 45 are found in
the park of Montsouris, and 462 in the centre of
Paris.

The Microbes of Running and Drinking Water. —
Water, whatever be its source, contains many more
microbes than air. They are even found in spring-
water taken from its source, which shows that they
exist in the interior of the earth. The following is
Miquel's estimate, which will give an idea of the
quantity of microbes found in Paris water, taken from
different places : —

Source of water. No. of microbes

to the litre.

Condensed aqueous vapour ... .„ .« .« ... 900

Water from drain, Asnieres 48,000

Rain-water 64,000

Vanne water (Montrouge basin) 248,000

Seine water (from Bercy, above Paris) 4,800,000

Seine water (from Asnieres, below Pari-,) ... 12,800,000

Sewer-water (from Clichy) ... 80,000,000

166 MICROBES, FERMENTS, AND MOULDS.

These numbers are the minima. The putrefaction
of stagnant sewer-water produces germs from which,
in a few days, microbes are multiplied by thousands.

Certes, in France, and Maggi, in Italy, have lately
been occupied with the micrographic study of drink-
ing-water. These observers reveal the presence of
microbes in the water under examination by means
of staining reagents. The reagent most in use is a
1*5 per cent, solution of osmic acid (Certes). Osmic
acid kills the microbes without changing their form,
and precipitates them to the bottom of the glass
vessel, whence it is easy to collect them. A cubic
centimetre of the solution suffices for 30 or 40 cubic
centimetres of water. It is allowed to settle, then
the liquid is poured off, and the thick, dark-coloured
deposit which remains consists of all the organisms
previously diffused in the liquid, and may be examined
under the microscope. The only drawback to the
use of this reagent is the high price of osmic acid,
a matter worth consideration in the extensive and
comparative researches necessary in these cases.
Maggi obtained analogous results with chloride of
palladium, and Certes with iodide of glycerine, and
alcoholic solutions of cyanine, gentian, etc. ; but none
of these reagents are as efficient as osmic acid, of
which the effect is more precise, constant, and durable.

Microbes of the Soil. — The presence of microbes in
the soil has been proved by Pasteur and his fellow-
workers, Chamberland and Roux, in the researches into

THE MICROBES OF HUMAN DISEASES. 167

the nature of anthrax, of which we have spoken above.
These observers collected earth in the neighbourhood of
trenches in which animals which had died of anthrax
had been buried, and found that not only on the surface,
but at some depth, this earth was full of bacteridia
(Bacillus anthracis), and also of many other microbes
or germs, of which the inoculation might produce more
or less dangerous diseases in animals. In order to
procure earth in a more perfect state of division, it
occurred to Pasteur to collect the excrement of earth-
worms, which consists almost exclusively of clay, rich
in humus or vegetable earth, on which the worms
are nourished. This earth, after passing through the
intestinal canal of worms, still contains microbes which
have not lost their virulence. As we have already
said, spring water, on issuing from the soil, contains
microbes which it has acquired in filtering through
geological layers; and we have also mentioned the
living microbes of chalk, dating, as Be'champ believes,
from the secondary epoch.

Telluric and Diblastic Theories. — Hence, it is in-
telligible that a theory should have been formed,
ascribing most epidemic diseases to the influence of
microbes of the soil, which can at a given moment
enter the human body, first by penetrating into the.
lungs and digestive organs, and thence into the blood.

Two German discoverers, Pettenkof er and Nageli,
set forth this telluric theory of disease, and several
facts confirm it. It explains why intermittent fever, or

168 MICROBES, FERMENTS, AND MOULDS.

malaria only prevails in marshy countries when the
marshes are partially dry, and especially in summer.
In order to make such country healthy, the marshes
must be completely dried and filled up, and then
transformed into cultivated ground. So, again, the
river valleys in France only become unhealthy when
the stream returns to its bed, leaving the adjoining
meadows transformed into marshes, which gradually
dry up and send forth into the air a host of spores,
produced by the schizophyta deposited by the water.
Finally, great excavations of earth diffuse through the
atmosphere the dormant spores brought thither by rain,
and remaining in a desiccated state in the soil.

In many cases, the intervention of two microbes of
different kinds have been assumed to explain the nature
and progress of great epidemics, such as cholera, yellow
fever, and typhoid fever. This is termed by Nageli the
diblastic theory (or that of two producing agents of
disease). Thus the microbe of malaria, or intermittent
fever, which is not contagious, often predisposes the
patient to receive the attacks of another zymotic
disease, such as cholera or typhoid fever. The two
microbes may subsist simultaneously in the human
frame, and their joint action may weaken the organism
at the expense of which they live and multiply.
Numerous cases might be cited to support this theory,
and the following examples may be given : —

" In the summer and autumn of 1873 the town of
Spires was visited by cholera, which was limited to

THE MICROBES OF HUMAN DISEASES. 169

the lower part of the town, situated on the banks of
the Speyerbach. There was a hospital for old men,
situated in the high part of the town, a quarter which
remained free from cholera, but 24 out of the 200
pensioners whom the hospital contained were attacked
by the disease. Now 33 of these men, the most able-
bodied among them, had been employed to dig up
some blighted potatoes in a field which lay very low,
almost on a level with the water which had collected
in a deserted sand-pit. They had not drunk of the
water in this field, neither had they passed through
the part of the town visited by the epidemic : 20 out
of these 33 men had cholera, and only 4 others out of
all the inmates of the hospital contracted the disease"
(Nageli).

Observations made on board English transports
on the voyage from India give analogous results.
"Detachments of equal number from two regiments
embarked on the same steam transport. A few days
later, cholera declared itself and carried off many
soldiers, all belonging to one of the two regiments,
and coming from a camp in which there was a violent
outbreak of cholera shortly after their departure. The
detachment from the other regiment, coming from a
place exempt from cholera, altogether escaped." Here
the influence of the locality and the soil is evident ; it
was the sole and essential agent of the disease, since
the contagion could not have occurred on board ship,
in which the conditions are generally healthy, neither

170 MICROBES, FERMENTS, AND MOULDS.

by contact with the men, nor by that with the
clothes and baggage, which were mixed together.
The cholera microbe which had been brought on
board ship could only act on the detachment mias-
matically predisposed by their previous residence in
an unhealthy place, containing the malaria microbe
(Nageli).

Miasma and Microbes. — This leads us to say a few
words on the term miasma, formerly in such common
use, and now without meaning. Before the existence
of microbes and air-germs was known, the doubtful
and mysterious principles which were believed to be
the cause of virulent and contagious diseases were
termed miasmata, and these miasmata were generally
supposed to be gases. It is now* proved that this cause
resides in solid, living particles, the microbes and their
germs: the term miasma is less and less employed,
or serves to designate air-germs. When, therefore,
Nageli uses the word, he regards it as synonymous
with microbes or air-germs.

The Question of Privies. — Hence it follows that
it is erroneous to apply the name of miasmata
to true gases, some of which exert an injurious in-
fluence on the human system. Such are sulphuretted
hydrogen and ammonium sulph-hydrate which are
disengaged from privies, and produce the disease called
plomb in the men employed to empty them. These
gases are deleterious to microbes as well as to men;
microbes cannot co-exist with them, which is perhaps

THE MICROBES OF HUMAN DISEASES. 171

the reason why these men seem to enjoy an immunity
from most contagious diseases.

People are too much disposed, when an epidemic
is prevalent, to accuse the privies, of which the
emanations are, under ordinary circumstances, only
offensive to the smell. When theso places, as well as
the sewers, are properly constructed, they present no
danger. But it is necessary that there should be
a sufficient flow of water in both to cover the solid
matter. We know, in fact, that if microbes are present,
they only become dangerous when dry enough to float
in the air.

In an epidemic of typhoid fever, for instance, the
soiled body and bed linen of the patient are much more
dangerous than the privies, in which, however, there
is a much larger number of microbes. The linen,
therefore, as well as the contaminated rooms and
furniture, should be immediately disinfected in the
mode prescribed by sanitary authorities.

The system of directing everything to the sewer,
which is now universally applied to large towns, and
which has encountered much opposition, is certainly
excellent when properly understood and applied. The
cesspools, as well as the cemeteries, ought to be as
remote as possible from the houses of the living. It
is as much opposed to public health to retain cesspools
which are gradually filled in the course of years, in
the midst of a town, as to have intramural cemeteries.
Everything should be carried off by the sewer, pro-

172 MICROBES, FERMENTS, AND MOULDS.

vided there is a sufficient flow of water to take all
solid matters with it and completely cover them.
These are deposited in places assigned for them, which
must necessarily be very remote from thickly populated
places. When these matters are then spread over
a large surface to dry in the air, the oxygen becomes,
as Pasteur has said, the great purifier of microbes.

In Paris, some of the sewage water of the great
main sewer is diverted on to the peninsula of Genne-
villiers, and it is then directed into gutters to serve as
a manure for market gardens. After filtering through
the cultivated plots, the water flows off in a limpid
stream.

Cornilleau, whose medical practice is at Genne-
villiers, has recently issued a report, showing plainly
that the sewage is but a slight source of danger to
the inhabitants of the peninsula. During the serious
outbreak of typhoid fever which occurred in Paris in
1882, there were only two typhoid cases in the whole
commune, and these cases were imported from Paris.

II. MICROBES OF THE MOUTH AND DIGESTIVE CANAL
IN A HEALTHY MAN.

Since there is a profusion of microbes in the air,
we can easily understand why they should be found
in the human mouth, and hence in all parts of the
digestive canal. They are for the most part harmless,

THE MICROBES OF HUMAN DISEASES. 173

as long as the epidermis of the mucous membrane
covering the intestinal canal is healthy. Pasteur has
shown that they are not found in the blood of a
healthy man, but that the slightest lesion of the
mucous membrane suffices to introduce them into the
circulation.* This fact was proved by experiments
made at Pouilly-le-Fort on sheep, inoculated with the
anthrax microbe by means of their food. The mortality
among these animals was notably increased when

Fizs 77 78.— Spirochate buccalis, and S. plicatilis, 6 (mixed with Vibrio rugula,
a), microbes in mouth of a healthy man.

thistles, bearded grain, or sharp-edged leaves were
mixed with their food, so as to cause little wounds in
their mouths, each of which served as an entrance for
microbes. As long as the microbes are few in number,
they perish quickly in the blood; but when the
number is considerable, the organism has not the power
to destroy them ; they soon compete with the corpuscles
of the blood, and the most serious diseases ensue.

Miquel estimates the number of spores introduced
into the human system by respiration, when the health

* This is not the case with fishes. Eichet and Ollivier have shown
that microbes are normally found in the blood of sea-fish, without
affecting their health.

174

MICROBES, FERMENTS, AND MOULDS.

is perfectly sound, at 300;000 a day, and 100,000,000
a year. It is evident that these germs, always
present, may easily become the source of diseases, of
which thrush in the mouth of infants, and of sick and
dying adults, is one of the least alarming.

Sternberg, surgeon of the United States army,
1880, writes : " When I was occupied in the micro-

Fig. 79. — Vibrio rugula (Warming) in different stages of development : &, c,/, indi-
viduals with vibratile cilia (flagellum); /', ciliated spores. Found in the human
mouth and intestines.

scopic examination of foul river water at New Orleans,
I used to find in my own mouth almost all tjie
organisms which were present in the putrefying liquid
I was examining — Bacterium termo, Bacillus subtilis
(Fig. 80), Spirillum undulatum,&nd a variety of minute
spherical forms and of rods, difficult to classify except
under the generic names of Micrococci and Bacteria.
Another organism which I have often found in healthy
human saliva is a species of Sarcina, perhaps identical
with S. ventriculi"

But the organism most commonly found in the
human mouth, which attracts attention from its large

THE MICROBES OF HUMAN DISEASES.

175

size and its abundance, is Leptothrix buccaiis. It is
never absent from the rough surface of the tongue
or the interstices of the teeth, and even those persons
who make a frequent use of the tooth-brush are not
exempt from it. In the latter case, however, it only
appears in the form of short, scattered rods ; while in

Fig. 80. — Bacterium (Bacillus') subtilis (Zopf), in different stages : A. cillatod rods ;
K, F, spores ; G, Zoogloea. In infusions of hay, and in the human mouth (much
magnified).

other cases, tne tufted stems of its vigorous growth
abound in the saliva, and are often established on the
epithelial cells, whence they may be detached by friction.
Sternberg compares the human mouth to a culture
apparatus, in which the germs of microbes find an even
temperature and the moisture necessary for their
development naturally provided for them— conditions
which can only be artificially produced in the
laboratory.

176 MICROBES, FERMENTS, AND MOULDS.

III. THE VIRULENT MICROBE OF HEALTHY HUMAN
SALIVA.

Pasteur and Vulpian in France, and Sternberg in
America, discovered almost simultaneously that the
human saliva may, under conditions with which we
are still imperfectly acquainted, become virulent, and
that this virulence is due to the action of a Micrococcus,
normally present in the saliva, a microbe quite distinct
from that of rabies, of which we have already spoken.

It is only known that this micrococcus is very
common in the saliva of a healthy man, and that in
some individuals the saliva is exceptionally virulent.
When injected under the skin of healthy rabbits, it
produces grave affections, often resulting in the animal's
death. These affections are due to the presence of
the micrococcus, since the saliva becomes harmless as
soon as these organisms are removed from it.

Sternberg informs us that his own saliva is
among those which possess this curious and alarming
property. He regards the more abundant nutriment
which this microbe finds in the mouths of some
persons as the cause of this virulence, since thus its
development is more energetic. "In my own case,"
he writes, "there is a very abundant secretion of
saliva. . . . My culture experiments show that this
micrococcus multiplies very rapidly, and in virtue of
this faculty it has for a certain time the advantage

THE MICROBES OF HUMAN DISEASES. 177

over Bacterium termo, which appears to be fatal to
the former when piesent in any number. ... In
my culture flasks, a small drop of blood from an in-
fected rabbit gave birth within a few hours to such
a number of microbes that the liquid contained in the
flask was completely filled with them, and it was
deprived of the nutriment necessary for any further
development."

The exceptional virulence of this microbe must
therefore be ascribed to its vital and reproductive
energy, and to the rapidity with which it multiplies ;
at any rate, until we know more on the subject.

IV. THE MICROBES OF DENTAL CARIES.

Miller's recent researches (1884) tend to show that
dental caries is chiefly due to the development of one
or more species of bacteria. The presence of acids
introduced into the mouth, or developed by certain
diseases (ulcers, thrush, etc.) which are themselves
produced by microbes, appears to be the predisposing
cause of this affection. These acids begin by softening
the dentine, deprived at some point of its superficial
coating of enamel, and through this the bacteria enter.
Saliva can be rendered experimentally acid by mixing
it for four hours, at a temperature of 20°, with sugar
and starch (Cornil). Hence the injuriousness of sugar-
plums and other sweetmeats, long and correctly

178

MICROBES, FERMENTS, AND MOULDS.

supposed to be the cause of the early decay of teeth,
especially in children who eat them in excess.

The microbe which Miller has
found to be most common in de-
cayed teeth is very polymorphic.
Microccocus, bacterium, chains and
filaments, are only different phases
of the same plant, which also pro-
duces acid fermentation in the
mouth, and the formation of lactic
acid. Within the dentine tubules,
a section examined under the
microscope shows all the inter-
mediate stages between the isolated
micrococcus and the filaments
(Figs. 81, 82). Miller succeeded
in producing this disease in sound teeth artificially.

Fig. 81.— Bacterium of dental
caries in the dentine tu-
bules: a, artificial caries;
b, spontaneous caries.

Fie 82 —Bacterium of dental caries : a, 6, different forms obtained in gelatine
culture.

According to his experiments, the best dentifrice for

THE MICROBES OF HUMAN DISEASES. 179

the destruction of microbes is a solution of corrosive
sublimate (mercuric chloride), one part in 1000, which
can be further diluted by four parts of pure water.

V. MICROBES OF INTERMITTENT OR MALARIOUS
FEVERS.

We say microbes in the plural, since it is almost
certain that the different types of intermittent fever,
tertian, quartan fever, etc., are produced by different
microbes ; moreover, it is probable that these microbes
vary with the locality. That of intermittent fever
in France is probably not the same as that of the
malaria, or fever of the Pontine marshes in Italy ;
and the African fevers, again, are probably produced
by a different organism.

Intermittent fevers are the first internal diseases
of which the vegetable parasitic nature was sus-
pected. Before that time we were only acquainted
with the parasites. of the skin, and with the entozoaria
and epizoaria (intestinal worms, lice, acari, etc.), which
are animals. In 1869, Dr. Salisbury, of Cleveland, U.S.,
entered on researches which led him to the con-
clusion that intermittent fever in the marshy valleys
of the Ohio and the Mississippi must be ascribed to
the presence in the system of a filamentous alga
which approximates to the genus Palmella. The
spores of this alga are constantly found in the saliva

180 MICROBES, FERMENTS, AND MOULDS.

of the subjects of intermittent fever. By exposure
during the night of little glass plates in marshy
meadows, Salisbury was able to collect similar spores,
which settled on the lower surface of the glass, and
were found floating in the drops of condensed dew.*
On passing through these marshes in the evening,
there was a peculiar sense of dryness in the throat,
and expectoration revealed the presence of spores of
Palmella. Finally, earth taken from these marshes
was found to be full of the same organisms.

When the marsh begins to dry up, the spores are
produced in abundance, and intermittent fevers occur.
Salisbury writes that " in 186*2, the weather was very
wet until about the 1st of July ; but that during
July, August, and September, there was hardly a drop
of rain. The springs and water-courses were nearly
dried up, the marshes and wet grounds also became
dry, vegetation was almost completely arrested, and
the whole country presented an arid appearance.
Shortly after the drought began, intermittent fever
made its appearance in all the unhealthy districts, and
spread so rapidly during the months of July and
August, that it attacked almost every family living
on marshy ground.

"A low, peaty meadow extends along the canal

* We must repeat what has been said before, that the presence
of these spores in the air is quite independent of that of the vapour
which constitutes dew ; in other words, the vapour does not transport
these spores, which must, on the contrary, be perfectly dry before they
can float in the air and settle on any damp object.

THE MICROBES OF HUMAN DISEASES. 181

to the south-east of the town of Lancaster, and the
neighbouring valleys are low and damp. The third
quarter of the town, touching on this meadow, and
all that part which is not raised from 35 to 40 feet
above the level of the meadow, have always been
districts in which attacks of intermittent fever are
prevalent. Those who live near the marsh are liable
to annual attacks of fever from May to November.
In August and September these attacks are generally
the most severe."

We said that moisture does not favour the trans-
port of microbes and their spores through the air,
but the remark does not apply to fogs, in which
numerous spores are found. We know that fogs are
formed of minute globules of water, which float in
the atmosphere, and of which the vapour of our
breath, only visible in cold weather, can give us an
idea. These globules of water float in the air just as
spores and all kinds of dust do, without wetting
the spores or running together, since as soon as this
occurs, the fog ceases to be ; it is condensed, and falls
in the form of more or less fine rain. Salisbury has
ascertained that there is a certain connection between
fogs and intermittent fevers, and this explains why
people are more apt to contract fever in the morning
and evening, at which times there is in summer always
a fog floating to a varying height above marshy places.
In a farm near Lancaster, the farmer and his wife, who
slept on the first floor, were attacked by tertian fever,

182 MICROBES, FERMENTS, AND MOULDS.

while their seven children, who slept on the second
floor, escaped. Salisbury ascertained that there was
a fog every morning, rising from a reservoir which
had been recently made. This fog reached the house
and rose above the first floor, but not as high as the
windows of the second floor, and penetrated into the
parents' bed-chamber through the open window. This
vapour had the same smell as the marsh, which was
covered with fever algae (Palmella febrilis), and pro-
duced the same feverish dryness in the throat and
pharynx. The vapour dispersed soon after sunrise,
and before the children had left their chamber.

Salisbury likewise ascertained the polymorphism
of Palmella febrilis, a polymorphism which is con-
firmed by the recent observations of the skilful
naturalist Zopf, and this fact explains the mode in
which an aquatic alga can live in the human blood,
in the form of Bacillus or Spirillum.

Still more recently (1879), marsh fever, or malaria,
which is so common in Sicily and in the Roman
Campagna, have been studied from the same point
of view by Crudeli, Cuboni, Cecci, and others, who
ascribe the disease to a vegetable parasite which they
call Bacillus malaria. This bacillus is abundantly
found in the blood of patients during the period of
attack, while during the period of acme which ter-
minates each attack only spores are found. The same
microscopic organism is found in all the malarious
districts of the Koman Campagna, and it can be

THE MICROBES OF HUMAN DISEASES. 183

produced in artificial cultures. It is not found in the
healthy parts of Lombardy. In the strata of air
which float above malarious ground in summer, this
microbe is so common that it is found in abundance

in the sweat of the forehead and

hands (Fig. 83).

This organism is not only

capable of cultivation, but rabbits

and dogs can be inoculated with
bacillus ^ so ™ to produce marsh fever

in them.* The lesions which
are observed in an autopsy are the same as those in
man, showing that the site preferred by the microbe is
the spleen and the marrow of the bones.

The fact that the bacillus ' and its spores are suc-
cessively found in the blood explains the intermittent
type of the disease, tertian, quartan, etc., according to
the variety of marsh fever. According to its variety,
and perhaps to the species of Schizophytum, the com-
plete evolution of the plant sometimes demands 48,
sometimes 72 hours, and the access of fever always
corresponds with the period of greatest activity in
the bacillus — that which precedes the emission of
spores.

Two military surgeons, Laveran and Richard,

* It is generally believed in France that animals, and especially
herbivora, cannot contract intermittent fever. This opinion is erro-
neous. It is known that in Italy cattle contract this fever when they
are not acclimatized to marshy districts, and that they are cured by
sulphate of quinine.

184 MICROBES, FERMENTS, AND MOULDS.

have also observed the parasitic nature of intermittent
fever in Algeria. The organism which they have
constantly found in the blood of those affected by
marsh fever presents several different aspects, but
appears especially to attack the red corpuscle of the

Fig R4.— Parasite of intermittent fever (La veran): A, normal haematin; B, B, corpuscle
No. 1 ; C, corpuscle No. 2, motionless ; D, corpuscle No. 2, containing mobile
pigmented grains ; E, corpuscle No. 2, provided with mobile filaments ; G, detached
mobile filament ; H, H, corpuscle No. 3 ; I, K, corpuscle No. 2, of small size,
red and agglomerated ; L, L, hfematins to which the small corpuscles No. 2 are
attached ; M, pigmented leucocytes, their nuclei made visible by carmine.

blood, in which, according to Laveran's expression,
" it is encysted like a weevil in a grain of wheat."

THE MICKOBES OF HUMAN DISEASES. 185

This observer thinks that it approximates to the
alg*e of the genus Oscillaria * (Fig. 84).

The different forms taken by this organism are
only the successive phases of its development, and
have not yet been observed by a competent botanist,
who alone can indicate precisely their true nature.
At a certain period of its existence the parasite
attaches itself to the red corpuscle of the blood, and
is nourished at its expense. The corpuscle turns pale,
loses its colouring matter, and disappears, leaving as
residue a small grain of pigment, representing the
haemoglobin absorbed by the parasite. Two or three
mobile filaments arise from the encysted parasite,
which resemble vibrios, and move rapidly in the blood
as soon as thoy become detached. Laveran states that
he has found the same organism in malaria patients
at Rome; and Richard found them in the blood of
a sailor just returned from China, who was suffering
from intermittent fever. The use of the microscope
permits an accurate diagnosis of this disease.

The spherical bodies, or the microbe in its encysted
form, announce that the attack is imminent, and no
time should be lost in administering sulphate of
quinine. Richard writes that " the multiplication of
these bodies must be extremely rapid. For instance,
in tertian fever they are not found in the intervals
of the attacks (apyrexiv). As the attack approaches,

* Rfcue Scientifique, April 29, 1882, p. 527; January 27, 1883,
p 113.

186 MICKOBES, FEKMENTS, AND MOULDS.

they appear in increasing numbers, and their maximum
corresponds with the beginning of the rise in tempera-
ture; from that moment they begin to perish, since
the heat of fever is fatal to them, and completely
checks their development. This explains the inter-
mittent character of the disease. They produce fever,
the fever kills them and then subsides ; when apyrexia
occurs they multiply again, excite fever, and so on."
Thus there is a successive series of auto-infection by
the parasite itself, unless its development is arrested
by sulphate of quinine. "The parasites of typhus
and typhoid fever are not affected by a temperature
of 40°, and even of 42°, and hence the continuous
character of these fevers."

Cornil has, with some justice, criticized Laveran's
description and illustrations of the parasite of marsh
fever. It is difficult to recognize in it an organism
really belonging to the animal or vegetable kingdom.
The form of the filaments which, as he asserts, issue
from the so-called encysted bodies, resemble those
which Hoffmann has seen and drawn in blood in its
normal state, and also in various diseases, and are
probably only expansions of extravasated protoplasm
in the red corpuscles at a temperature of 40°. The
encysted bodies are also, according to all appearance,
only blood-corpuscles, more or less affected by disease.

There only remain the pigmented, encysted granules
in the red and colourless corpuscles, granules which
have been observed by others, and especially by

THE M1CKOBES OF HUMAN DISEASES. 187

Marchiafava and Celli. But experiments undertaken
to show that these granules are microbes have as yet
afforded no certain results.

In short, Cornil remarks : " Since bacteria are
found neither in the internal organs nor in the blood
of those who die of intermittent fever, we are tempted
to suppose that the virulent agent resides in the sur-
face of the mucous membrane — for example, in that of
the digestive canal ; and that the chemical poisons pro-
duced under the influence of these micro-organisms
penetrate thence into the blood. They then act on
the red corpuscles of the blood."

Finally, we must remember that many continuous
fevers, especially those of hot countries, seem to be
complicated by the presence of two parasitic elements,
as we have said in describing Nageli's diblastic theory.
To the marsh microbe, which comes from the soil,
another is added, of which the immediate origin is
due either to direct contagion, or to some other telluric
or atmospheric local influence.

VI. RECURRENT FEVER AND YELLOW FEVER.

We place these two diseases together, simply
because they have rarely been observed in France.
Recurrent fever, or relapsing typhus, is a disease
which has been observed in Germany, Russia, Ireland,
and India, in which latter country it is called jungle

188 MICROBES, FERMENTS, AND MOULDS.

fever. In all these countries poverty, scarcity, and
famine appear to be the predisposing causes. In
this case, the presence of microbes in the human
blood has been established in the clearest and most
incontestable way. This discovery was made by
Yirchow and Obermeier in 1868, but nothing was
published on the subject until 1873.

The symptoms of the disease are very like those
of typhoid fever. The microbe, which may always
be found in the blood, and which characterizes the
disease, is a Spirillum or Spirochcete (S. Obermeieri) ;
that is, a filamentous organism, twisted into several
spirals, and animated by very lively movements (Fig.
51, w, o). These spirilla may be seen moving in
thousands among the blood-corpuscles, when these are
placed under the objective of the microscope.

The difficulties experienced by the original
observers in their attempts to inoculate man or
animals with the disease, and the fact that in some
cases the microbes appear to be absent from the
blood of affected persons, have thrown some doubt
on the relation between the disease and its microbe.
This is because the conditions of the existence of
this plant in the system were not sufficiently con-
sidered. Albrecht has recently shown (1880) that
blood which apparently contains no spirilla will, if
kept in a culture-flask for some days, protected from
air-germs, become full of these organisms at the end
of that time, a proof of the pre-existence of the spores

THE MICROBES OF HUMAN DISEASES. 189

The same observer was able to point out the spores,
which are only visible under a magnifying power
of 1000 diameters, and which succeed to the spirilla
during the remittent period. Moreover, a monkey was
successfully inoculated with the disease at Bombay,
and after the lapse of five days spirilla were found
in the animal's blood.

Yellow fever has not yet been sufficiently studied
in the countries in which it prevails, but there can
be no doubt that it is likewise produced by a special
schizophytum. Originating, as it appears, in North
America, probably in the delta of the Mississippi, this
disease has been spread by maritime commerce over
the whole intertropical zone of the globe. The centres
of infection are always on the sea-board, at the mouths
of great rivers, from which we conclude that its special
microbe is found in its free state in the brackish
marshes formed at river-mouths.

The medical men of Rio de Janeiro, and particu-
larly Freire, have lately described and published illus-
trations of microbes said to have been observed by
them in the faeces of patients attacked by yellow
fever. But their drawings are for the most part
fanciful, and betray great inexperience in the methods
of research and- in microscopic examinations; for
instance, the air-bubbles, unskilfully interposed in
the preparations which their author thought worthy
of photographic reproduction, figure as microbes.
Thanks to the accuracy of photography, which leaves

190 MICROBES, FERMENTS, AND MOULDS.

no scope for the fancy of a draughtsman, there can
be no doubt as to the gross error committed by the
observer

As for Freire's attempts at vaccination, his own
statistics are far from being favourable to his method ;
in fact, they prove that vaccination increased the
rate of deaths in the proportion of 19 per 100.

Much more scientific researches were undertaken

Fig. 85.— Section of kidney in yellow fever (Babes), showing a capillary vessel, c,
filled with chaplets of micrococci.

by Cornil in Paris, on some anatomical preparations,
preserved in alcohol, which were sent from Brazil.
He found in the liver and kidney of the victims of
yellow fever, chaplets of micrococci or bacteria (Fig.
85), only visible under a very strong magnifying

THE MICROBES OF HUMAN DISEASES. 191

power (more than 1000 diameters). But they are not
invariably present, and it is consequently uncertain
whether they are the cause of the disease. From its
symptoms and lesions, there is reason to think that
the parasite or parasites — for there may be several,
according to Nageli's theory — have their seat in the
digestive canal. New and sustained researches, carried
on in countries where yellow fever prevails, and more
methodically .conducted, are necessary to elucidate this
question.

VII. TYPHOID AND TYPHUS FEVERS.

These two diseases may be taken together, since
in both the digestive canal is the part chiefly affected.

Here crowding, the aggregation of men and the
human miasmata resulting from it, play the chief
part, admitting, as we have already said, that miasma
means microbe. We need not, therefore, deny the in-
fluence of predisposing conditions, or what is called
receptivity for the disease. These unfavourable con-
ditions are: physical exhaustion, bad food, youth,
mental emotion — all which conditions are allied with
human miasmata, the result of crowding in barracks,
where typhoid fever prevails; in camps, which are
more subject to typhus; and in the badly built
houses of our large cities.

In few diseases is the influence of anti-hygienic

192 MICROBES, FERMENTS, AND MOULDS.

conditions more apparent. Want of air and cleanli-
ness is one of the principal factors of these cruel
epidemics. In the confined lodgings of the artisans
of large cities, the dead, the sick, and the healthy
man may be found sharing the same room and even
the same bed; linen impregnated with typhoid ex-
cretions may remain for days in the same chamber.
The walls and floors of our barracks, too rarely cleansed,
disinfected, or whitewashed, harbour myriads of mi-
crobes ; and the water of adjoining wells likewise con-
tains them in great numbers.

Nor can it be said that hygienic conditions are
more carefully observed in the rural habitations of
villages and detached farms. The peasant is as
ignorant of the laws of health and cleanliness as the
artisan; the neglect of the builder, often a mere
mason, of the landlord and the tenant, is still more
striking in country districts. For this reason epi-
demics are generally more fatal in the country than
in towns ; but they are less frequent, of shorter dura-
tion, and more easily localized in a village or detached
farm, since in this case there is a large supply of
oxygen, which is the great destroyer of microbes.

With respect to typhoid fever, one of the most
common diseases in this country, the lesions by which
it is always characterized show that the microbe pro-
ducing it is chiefly found in the mucous membrane of
the intestines, in Peyer's glands, and in the isolated
follicles which cover this membrane, and which are

THE MICROBES OF HUMAN DISEASES. 193

always hypertrophied and softened in typhoid patients.
The round red spots which may be observed upon the
skin are distinctive marks of the affection of the diges-
tive canal, and it has occurred to Bouchardat that if, as
he supposes, these spots contain the same microbe as that
of the intestines, it might be cultivated and attenuated
into a true vaccine.

The presence of special microbes in typhoid fever
was first observed by Recklinghausen in 1871, but the
exact description of the typhoid bacillus has been only
recently given by Eberth and Klebs.

Eberth has observed this bacillus in the spleen,
the lymphatic glands, and the intestines, making
use of special staining processes. It appears in the
form of short rods with rounded extremities, in the
tubular glands and round the bottom of these glands,
which cover the mucous membrane of the intestine.
They are numerous when the ulceration of Peyer's
glands begins; afterwards they become fewer, and
are succeeded by other microbes. From the position
of the bacteria in a section of the mucous membrane,
it may be seen that they penetrate through its surface,
and fasten on the ulcerated and mortified tissue
(Cornil).

Blood taken from living patients often displays
bacilli amid the red corpuscles (Fig. 86). The spleen,
which is always hypertrophied, contains the same
bacillus, which is also found in the liver, and some-
times in the kidneys and urine.

194 MICROBES, FERMENTS, AND MOULDS.

Many other bacteria appear in the intestines when
the disease is approaching its end, but the bacillus in
question is the only one found in the blood and
internal organs, so that it is really characteristic of
the disease.

Gaffky, a German micrographist, and a pupil of
Koch, has succeeded in the artificial culture of this
microbe, taking it from the spleen of persons who died
of typhoid fever. It is actively developed on gelatine
and potatoes, becomes very lively and produces endo-

Fig. 86. — Bacilli of typhoid fever (x 1500 diam.): three red corpuscles may be
observed in the same preparation.

genous spores at a temperature of 38°. But the inocu-
lation of animals with the disease has hitherto been
unsuccessful, at least so as to reproduce in them an
affection of the intestines, really resembling that of
Peyer's glands in man.

The horse is the only animal affected by a similar
disease, which has also been called typhoid fever. In
1881, the horses of the Paris Omnibus Company were
decimated by an epidemic of this nature. But the
lesion of Peyer's glands cannot be compared with that
which occurs in the same glands in man, and no
special microbe has yet been discovered.

THE MICKOBES OF HUMAN DISEASES. 195

The presence of the bacillus of typhoid fever in
the air or in water has not yet been ascertained.
Neither is anything known about the microbe which
may be assumed to be the cause of typhus fever.

VIII. THE CHOLERA MICROBE.

This terrible disease has its origin in Asia, where
its ravages are as great as those of yellow fever in
America. It is endemic or permanent in the Ganges
delta, whence it generally spreads every year over
India. It was not known in Europe until the begin-
ning of the century ; but since that time we have had
six successive visitations, and it seems destined to
replace the plague or black death of the Middle Ages,
a disease which appears to be now confined to some
few localities of the East.*

In 1817, there was a violent outbreak of cholera
at Jessore, India. Thence it spread to the Malay
Islands, and to Bourbon (1819) ; to China and Persia
(1821); to Russia in Europe, and especially to
St. Petersburg and Moscow (1830). In the following
year it overran Poland, Germany, and England, and
first appeared in Paris on January 6, 1832; here it
raged until the end of September.

* See in the Annuaire de ih&rapeutique, 1885, Bouchardat's
account of cholera epidemics in Paris, together with remarks on the
nature, the parasite, the hygiene, and the treatment of cholera.

196 MICEOBES, FERMENTS, AND MOULDS.

In 1849, the cholera pursued the same route.
Coming overland from India through Russia, it
appeared in Paris on March 17, and lasted until
October.

In 1853, cholera, again coming by this route, was
less fatal in Paris, although it lasted for a longer time
— from November, 1853, to December, 1854.

The three last epidemics, 1865, 1873, and 1884,
differ from the foregoing in not having taken the
continental route; they came by the Mediterranean
Sea. Brought from India to Egypt by the Mecca
pilgrims, the epidemic of 1865 entered France by way
of Marseilles, ravaged Provence during the summer
of 1865, and was carried to Paris towards the end of
September by a woman who came from Marseilles.
It was less fatal than the preceding epidemics, and
so also was that of 1873.

The epidemic of 1884 took the same route. First
localized in Alexandria (1883), it attacked Naples,
Marseilles, and Toulon in the summer of 1884, and
overran all Provence; thence it was transferred to
Nantes, to several towns in the north-west of France,
and to Paris, where it was comparatively mild. Finally,
it entered Spain at Barcelona towards the end of the
year, and ravaged the whole peninsula through the
summer of 1885. In August, it also reappeared in
Marseilles and Toulon, and this could not be ascribed
to a fresh importation from Spain or the East.

The essentially epidemic and contagious progress

THE MICKOBES OF HUMAN DISEASES. 197

of this disease clearly indicates the presence of a
microbe, of which the chosen seat is the intestines,
whence it passes with the patient's faeces, and con-
stitutes the contagious element in places affected by
the epidemic.

The first precise micrographic researches made on
this subject were those of the French and German
commissions sent to Alexandria in 1883. Koch,
member of the German sanitary commission, was
the first to describe the microbe which it has been
decided to consider as the producing agent of cholera.
He gave it the name of comma bacillus (Bacillus
komma), on account of its form.

In order to see these bacilli in any number, a case
of malignant cholera must be observed. For this
reason, an unsuccessful search for this parasite has
often been made, since it cannot be distinguished from
the numerous other parasites found with it in the
intestines of cholera patients on the second or third
day. A small fragment of the rice-water evacuation
of cholera should be placed on a glass slide and
stained with methyl violet or methylene blue; the
superfluous liquid must be drained off, and the pre-
paration may then be examined under a magnifying
power of from 1200 to 1500 diameters, making use
of an immersion lens, on which light is thrown by an
achromatic condenser.

The comma bacilli then present the appearance
shown in Fig. 87, and, in spite of the colouring matter,

198 MICROBES, FERMENTS, AND MOULDS.

are full of motion and activity, which they retain for
some time. They are arched in form, and, roughly
speaking, resemble a comma. Their length is 1 J micro-
millimetres to 2 J micro-millimetres, and their width is
0*6 to 07 micro-millimetre. They are often arranged
in chains or chaplets, so as to appear like the letter S,
or several S's, placed end to end, as we see in Fig. 87.
These latter are the most characteristic. Compared

; I/ »)&//•

Fig. 87. — Cholera microbe, or Bacillus Tcomma (Koch) : a-z, the different forms which
it presents in its growth and division into cells (greatly magnified) ; 1, 2, cultures
of bacillus, under a simple lens.

with the microbe of tuberculosis, that of cholera is
shorter and thicker. Its spiral shape has led to the
belief that it is an intermediate form between the
genera Bacillus and Spirillum.

Comma-shaped microbes may be found in most
stagnant and running water, but they are in general
much larger, and none of them present the charac-
teristic dimensions of Bacillus komma.

This bacillus is found in the riziform grains of
choleraic evacuations, which are, as we know, formed

THE MICROBES OF HUMAN DISEASES. 199

by the desquamation of the mucous membrane of the
intestines. The membrane is, in fact, literally flayed
from one end to another, and, in consequence of its
congestion, the walls of the intestines are of a bright
rose colour. The riziform grains consist of small
tufts of epithelial cells, conglomerated together, and
they contain numerous bacilli.

They are also found in the glands of the intestine
into which they penetrate, owing to the desquamation
of the epithelium. They have not as yet been found
in the kidneys, the urine, or the blood.

Cultures of this microbe on gelatine or gelose are
very successful. Koch has observed that it readily
multiplies in damp linen, or in milk, broth, eggs,
moistened bread, potatoes, etc. The temperature most
favourable to it is from 30° to 40°, and even at 20° it
still multiplies on gelatine. Below 16° it grows very
slowly, but does not perish. Cold does not kill it : at
10° below zero it is still alive, and capable of resuming
all its activity when replaced in favourable conditions.
This microbe is aerobic, and soon dies when deprived
of air.

Water can serve as its vehicle, but does not supply
sufficient nutriment, so that it soon disappears.
This, however, is not the case with stagnant water
containing organic matter. When the level of sub-
terranean waters sinks, the surface water becomes
more charged with all kinds of refuse, and the
multiplication of germs becomes more easy. Bacilli

200 MICROBES, FERMENTS, AND MOULDS.

cultivated in distilled water die within twelve hours,
while they can live for a week in drinking-water.
(Cornil.)

The influence of the level of the subterranean
waters on the progress of cholera epidemics was
pointed out in Germany by Pettenkofer long before
there was any serious idea of regarding a microbe as
the cause.

During his recent travels in India, Koch met with
the comma bacillus in the stagnant waters of that
country.

For a long while the attempt failed to reproduce
Asiatic cholera in animals by injections of comma
bacilli, and thus to prove the parasitic nature of the
disease. The animals in countries attacked by cholera
appear to enjoy immunity in this respect. Nicati and
Kietsch at Marseilles were, however, successful in pro-
ducing cholera by the direct injection of choleraic liquid
into the duodenum of guinea-pigs, dogs, etc. Almost
all these animals died at the end of two or three days,
and the inflamed intestines contained a number of
comma bacilli, much more vigorous than those of the
injection.

Bochefontaine, of Paris, swallowed pills which
contained choleraic evacuations. He felt unwell for
some days, but no serious consequences ensued. It
is probable that in this case the acidity of the gastric
juice attenuated, or partially destroyed the bacilli.
We shall see that acids are, in fact, adverse to the

THE MICROBES OF HUMAN DISEASES. 201

development of the microbe. Bochefontaine also
injected the choleraic virus under the skin of his arm,
but the operation was only followed by an oedematous
redness, localized round the puncture, and the con-
stitutional symptoms were not so marked as those
produced by taking the same virus into the digestive
canal.

Ferraris .Attempts at Inoculation. — This leads us
to mention the attempts at inoculation made by
Ferran on a large scale in Spain, under the name of
anti-cholera vaccinations.

In 1884, Ferran, a Tortosa physician, was sent by
the municipality of Barcelona to study the infectious
agent of cholera at Toulon. His preceding studies
in micrography pointed him out for this mission.
He returned from Toulon, provided with cultures of
the comma bacillus, and devoted himself to the
study of its life-history. The facts reported by him
differ very much from those previously observed, and
cannot be accepted without further investigation.

According to Ferran, the cholera microbe presents
a polymorphism which has escaped notice in Koch's
investigations, and those of the other micrographists
who have observed and cultivated it. When trans-
ferred to a sterilized alkaline infusion, the comma
bacillus increases in length, forms sinuous filaments,
then swells at one extremity until it attains to the
volume of a red blood-corpuscle, thus constituting
an oogonium filled with protoplasm. A transparent

202 MICKOBES, FEBMENTS, AND MOULDS.

envelope (periplasma) then encloses the oogonium,
which thus becomes an oosphere. Close to this, on
the original filament, a small swelling appears, which
Ferran regards as the pollinidium, or antheridium,
which is intended to fertilize the oosphere and trans-
form it into an oospore.

When the rupture of the oospore occurs, the
granules contained in it float in the liquid. Those
which have been fertilized grow until they are as
large as the original oogonium, and constitute mul-
berry-shaped bodies, so called on account of the
numerous round projections or micrococci which
cause the surface to resemble that fruit.

A very slender filament may soon be seen to issue
from one of the points of this mulberry-shaped body,
a filament which grows longer, and sometimes two
of them appear at once. These filaments become
sinuous, twist in spirals, form spirilla, and are then
segmented so as to form by fission Koch's comma
bacilli, which are the starting-point of the culture,
and of this cycle of evolution (Figs. 88, 89, 90).

Hence it would appear that the cholera microbe
must belong to a much higher group than that of
bacteria, to which it has been hitherto assigned.
This mode of reproduction would show that it is not
an alga, but a fungus of the group of Peronosporece,
and it is, in fact, termed by Ferran P. Barcinonce
while his friends prefer to call it P. Ferrani, after its
discoverer.

THE MICROBES OF HUMAN DISEASES.

203

FeiTan regards this peronospora as the infectious
agent of cholera. Yet it seems extraordinary that
such a remarkable polymorphism should have escaped
the observation of Koch and of the numerous micro-

Figs. 88, 89, 90.— Evolution of cholera microbe (Peronospora Ferrani: Ferrari :
1. Cholera microbe (Bacillus kmwma\ discovered by Koch. 2. Spiral form of
bacillus, transferred from gelatine to an infusion. 3. Degeneration of spiral
form after a series of successive cultures. 4. Cholera microbe (Peronospora
Ferrani) : development of oogonium on the spirilla and straight filaments.
5. The oogonium is filled with granules which centre in a point k, and it is then
converted into an oospbere ; m, pollinidium on fertilizing organ. 6. The oosphere
is converted into mulberry-shaped and comma-shaped bodies.

graphists who have made various cultures of the
comma bacillus. It is difficult not to suppose that
some negligence or error has vitiated Ferran's re-

204 MICEOBES, FERMENTS, AND MOULDS.

searches, and the first idea which will occur to any
unprejudiced micrographist, is that P. Ferrani is not
really Koch's comma bacillus, and consequently not
the cholera microbe.*

We have, in fact, already shown that numerous
comma-shaped bacteria, or free cells, are found in
water and in the human body, and that these may
be easily confounded with the true comma bacillus
when staining reagents and a very precise mode of
culture are not employed. Ferran himself states that
this staining process must not be used in the culture
of P. Ferrani. Cornil has, however, shown that the
true comma bacillus is not destroyed by methyl
violet. Finkler had previously discovered in cholera
nostras, which is not epidemic, a comma-shaped
microbe resembling in many respects the one
described by Ferran. Koch has shown that this
microbe, as well as one of similar form found by
Lewis in the saliva, does not act in cultures like the
microbe of Asiatic cholera ; Lewis's microbe does not,
like the cholera bacillus, liquefy gelatine.

The precautions necessary for the sowings of
culture liquids are so great that we may be permitted
to doubt whether Ferran has always guarded against
error. Brouardel's report shows, after a visit to

* Our criticism on the description and illustrations of Laveran's
marsh-fever microbe might be applied, word for word, to Ferran 's
description and illustrations of the cholera microbe, which we have
reproduced above.

THE MICROBES OF HUMAN DISEASES. 205

Ferran's laboratory, that the instruments and methods
in use there were primitive and insufficient.

Until these facts have been confirmed by other
observers, it seems prudent to regard P. Ferrani and
B. komma as two absolutely distinct microbes. It
does not follow that the culture liquids employed by
Ferran did not contain the latter, but it is probable
that it also contained, and in larger numbers, a second
microbe (?), which is Peronospora Ferrani.

It may also be observed, the injection of Ferran's
culture liquid into the intestines of guinea-pigs pro-
duced no effect, while subcutaneous injections soon
killed these animals and distinctly affected men. This
is precisely the opposite effect to that observed by
Nicati and Rietsch at Marseilles, and by Bochefontaine
in Paris.

This is a crucial difference, since it shows that
the two microbes are not identical, and all our know-
ledge of cholera tends to show that its microbe has
a special action on the intestines.*

However this may be, Ferran carried on his
culture experiments in the endeavour to obtain an
attenuated microbe which might serve for preventive
inoculations. He believes that he has succeeded, and

* The experiments made by Gibier and Van Ermengen in August,
1885, confirm this opinion. After inoculating a certain number of
guinea-pigs, according to Ferran's hypodermic method, with a virulent
culture liquid, and giving them time to recover, the same liquid was
injected into the stomach of these animals, and they all died with the
symptoms and lesions of cholera.

206 MICROBES, FERMENTS, AND MOULDS.

after inoculating himself, he performed the same
operation on several of his friends ; then on thousands
of people in different towns of the province of Barce-
lona, and throughout Spain.

His inoculation consists in introducing, by means
of the small syringe used for hypodermic injection,
about a cubic centimetre of the vaccinal liquid, the
nature of which is kept secret by its author. There
is alwa}^ a certain discomfort after the operation,
but it disappears at the end of a few hours. Ferran
himself states that one inoculation will not suffice
to ward off the contagion. A second, third, and even
more, are necessary for the attainment of this object,
but the discomfort caused by the operation always
becomes less.

Up to this time the results obtained by the pro-
cess during the recent epidemic in Spain are not
accurately known, since Ferran has been unable to
produce the official statistics which are necessary to
confirm his assertions.

We are, therefore, entitled to reserve our judg-
ment, both as to the value claimed for this vac-
cination, and as to the true nature of the microbe
cultivated by Ferran, and considered by him to be
the infecting agent of cholera. If, again, we recur
to the facts established by Bochefontaine, it may be
asked whether subcutaneous injection is the true
mode of inoculation applicable to this disease, and
if the process adopted by Bochefontaine, of intro-

THE MICROBES OF HUMAN DISEASES. 207

ducing the attenuated microbe into the stomach by
means of pills or a liquid, would not be more rational.

Mode of Propagation and Persistence of Cholera. —
The upper part of the delta of the Ganges seems to
be the original home of cholera and its microbe.
Below this region, the stagnant water on each side
of the river, infected with every species of ordure,
renders the maritime base of the delta wholly unin-
habitable. But even in its upper part the land is
nearly covered by water. In order to build a house,
the earth is heaped up to raise the level of the soil,
and the house stands on the embankment, surrounded
by water. A high temperature is necessary to enable
the bacillus to live in water, and it is probable that it
will never become acclimatized in our colder climate.
The drainage which has been carried on round Cal-
cutta has already rendered epidemics less serious.

The disease is always propagated by man. In
India, Arabia, and Egypt, its diffusion is chiefly owing
to pilgrimages. In Bengal the pilgrims all bathe
together in sacred pools, often only a few square
metres in size, and receiving some thousands of men
in the course of the day, streaming with sweat and
exhausted by long journeys and insufficient food, and
under such conditions cholera is often developed.
From India it passes to Arabia by means of the
Mussulman pilgrims, whose caravans block the nar-
row streets of Mecca every year, and thence it is trans-
ported to Egypt. Finally, it is carried from Alexandria

208 MICROBES, FEEMENTS, AND MOULDS.

to Marseilles and other Mediterranean ports by vessels
which have served for the transport of pilgrims, by
men, their linen, and other garments.

It is consequently by the human body and its
clothing, or by the water which carries away human
faeces or has served for the washing of soiled linen,
that the infecting microbes are carried. The air, as
it has long been known, need not be taken into
account. As early as 1832, it was observed that the
wind did not affect the epidemic, which seemed rather
to advance like a man travelling by short stages.

Duclaux's recent researches show that the sun
and air attenuate and soon destroy the microbes, and
that only dead germs are borne on the air and wind.
" In order to retain their virulence unimpaired, the
microbes must travel in packages of clothing, in bales
of merchandise, or in the close, moist hold of a vessel.
In a word, of all agents of sanitation, the sun is at
once the most universal, the most economical, and
the most active to which the guardians of public
and private hygiene can have recourse " (Duclaux).

Koch has declared that acids in general are the
greatest hindrance to the development of the cholera
bacillus. In this way, the acid of the gastric juice
is the best safeguard, and many cases of contagion
may be explained by the fact that the large quantity
of water imbibed has diluted the gastric juice to
excess, or else that the source of contagion has
rapidly passed through the empty stomach, and

THE MICROBES OF HUMAN DISEASES. 209

has carried a liquid containing dangerous microbes
straight into the intestines. Indigestion, and catarrh
of the stomach and intestines, of which diarrhoea is
a symptom, constitute predisposing causes of the
disease.

Among other substances unfavourable to the de-
velopment of the microbe, and thus constituting a
preventive of cholera up to a certain stage, we may
mention calcium sulphate, which acts by producing
sulphuretted hydrogen gas, also carbolic acid, salicylic
acid, thymol, alcohol, acetic acid or vinegar, and
mustard oil, which, like the other volatile substances
already mentioned, constitutes an excellent antiseptic
in an epidemic of cholera.

We shall speak in another chapter of the purity
of drinking-water, which is of great importance, and
of the improved niters invented to eliminate the
microbes which are not arrested by ordinary filters.

IX. THE EXANTHEMATA: SCARLATINA, SMALL-POX,
MEASLES, VACCINIA.

Microbes are found in the eruptions characteristic
of all these diseases. They are generally micrococci,
isolated or in chaplets.

Measles. — Babes, in 1880, was the first to describe
the micrococci which he observed in this disease, and
especially in the pneumonia by which it is often com-

210 MICEOBES, FEKMENTS, AND MOULDS.

plicated. The blood of the eruption, the catarrhal
secretion of the nose, etc., contain small round
bodies, isolated or in pairs (in the form of the figure
8), or more rarely in short chaplets. When there is
decided pneumonia, the pulmonary alveoli likewise
contain isolated bacteria, in the form of an 8, in
chaplets, and even in zoogloea, or massed together.
Babes has not yet cultivated nor tried to inoculate
this microbe.

More recently, in January, 1883, Le Bel observed,
in the urine of persons attacked by measles, the
appearance of slightly curved rods (bacillus) capable
of very slow movements. Their length varies con-
siderably, and the spores appear in a swelling which
occurs at about a third of the length of each rod.
This microbe appears for a few days at the beginning
of the fever, and disappears with the fever, to return
afresh at the moment when peeling begins. We know
that these are the two epochs of contagion. The
microbe is found in this scurf, and may be obtained
by scraping the skin with a knife. Le Bel succeeded
in cultivating it in sterilized urine. In serious cases
of measles, the microbe remains upon the skin and in
the urine for weeks, and even months. It is probable
that Babes' s micrococcus and Le Bel's bacillus are only
two forms of the same microbe.

Scarlatina. — Pohl has found, in the desquamating
epidermic cells of this disease, and on the soft palate,
micrococci of somewhat smaller size than those of

THE MICROBES OF HUMAN DISEASES. 211

measles. A bacterium in the form of an 8 has also
been found in the urine of scarlet-fever patients.

Stickler believes that he has discovered a vaccine
for scarlatina, by passing its virus through the horse
or the cow. When these animals are inoculated with
the blood of a man suffering from the disease, an
eruption accompanied by desquamation occurs three
days after inoculation. A man inoculated with this
desquamation displayed a rash resembling that of
scarlatina, and when the same man was afterwards
inoculated with human scarlatina, he did not take the
disease.

Small-pox and Vaccinia. — We find in small-pox
pustules micrococci, either isolated or united, which
may be seen on a section of the skin if they are
coloured with methyl violet. The same microbe may
be observed on the pustules of the mucous membrane
of the larynx, in the liver, the kidneys, and the blood
of the vena portae. The attempt to cultivate it has
hitherto failed.

The micrococcus found in small-pox pustules does
not differ in its form from that of cow-pox in cows,
which constitutes, as we know, the original source
of human vaccine. It is not yet certain that the
microbes of small-pox and vaccinia are identical, but
from the resemblance of the pustules and of the micro-
cocci contained in them, it is most probable that this
is the case, and this would explain why vaccine is
efficacious as a preventive of small-pox.

212 MICROBES, FERMENTS, AND MOULDS-

It may be useful to retrace here the curious history
of vaccine, since it is directly interesting to us all.

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:' ?'vi

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FiK 91 —Section of skin covering a small-pox pustule : a, horny layer of the
epidermis; d, adenoid tissue-; TO, m, micrococci stained with methyl violet (x
850 diam.).

Before vaccine was discovered, inoculation with
small -pox was practised as a preventive measure.

THE MICROBES OF HUMAN DISEASES. 213

This inoculation was known to the Arabs and Chinese
as early as the tenth century, but it was decried by
physicians, and only practised by women. In India
it was practised by the Brahmins, and a public crier
announced that he had small-pox virus to sell.

In 1717, Lady Mary Wortley Montague, wife of
the English Ambassador in Constantinople, chanced
to see the operation performed by an old Thessalian
woman, who always accompanied the puncture with
practices of witchcraft and superstitious usages. She
asserted that the Virgin herself had appeared to reveal
the secret to her, and boasted of having performed
inoculation in more than 40,000 cases. Lady Mary
was so much impressed by the results obtained that
she had her son inoculated, and it is said that the old
Thessalian handled her rusty needle so unskilfully
that Maitland, the physician attached to the embassy,
was obliged to finish the operation. On her return to
England, Lady Mary made the success of the experi-
ment generally known. George I. authorized the
inoculation of six prisoners in Newgate, and then of
six orphans. The operation was performed by Mait-
land and crowned with success, and he was then
allowed to inoculate members of the royal family,
and more than 200 other persons.

The practice was, however, condemned by the
clergy, who considered it to be immoral and anti-
religious, as being opposed to the divine rights and
will Some failures, such as the death of Lord Sunder-

214 MICROBES, FERMENTS, AND MOULDS.

land's son, awakened alarm, and caused inoculation to
be discredited.

Notwithstanding this, it was introduced into France
in 1723 by De La Costa, and accepted by Chirac,
Helvetius, and by other physicians of the day.
Although opposed by the majority, and officially con-
demned by a decree of the Sorbonne in 1753, as "un-
lawful and contrary to the law of God" — a decree
officially confirmed by the faculty of medicine in 1763
— inoculation continued to be practised up to the
time when vaccination was substituted for it.

Vaccination appears to have been practised in
Asia in earlier times. However this may be, it was
known in the south of France that farm servants who
had been affected by cow-pox were secured against
small-pox. These pustules generally occur on the
udder, and the milkers were inoculated with the
vaccine matter, through some accidental scratch on
their hands. Rabault, a Frenchman, communicated
this fact in 1798 to Pew, an English physician and
a friend of Jenner. To Jenner we must assign the
merit of understanding the importance of this fact,
and deducing from it one of the most admirable dis-
coveries of modern medicine, the preventive method
which continually tends to become more general, and
to be extended to other diseases, especially since
Pasteur's late researches into vaccination for anthrax
and for fowl-cholera.

Pasteur has also shown that the microbes are the

THE MICROBES OP HUMAN DISEASES. 215

active principle of the vaccine virus. The liquid need
only be deprived by filtration of its micrococci in
order to become inert, and consequently unfit for use
in vaccination.

X. THE MICROBES OF CROUP AND WHOOPING-COUGH.

The parasitic nature of croup and diphtheria, which
had long been suspected, was only shown in 1881
by the researches of two American physicians, Wood
and Formad. In the spring of that year a very
serious epidemic of croup occurred at Ludington, a
small town on the borders of Lake Michigan. Here
the principal industry is derived from the neighbouring
forests, the trees of which are sawn into planks in the
numerous saw-pits, and thus employ almost the whole
working population. The town stands on a height,
with the exception of one quarter of it, which is built
on very low, marshy ground, partly filled up with saw-
dust. Here the soil is so wet that when a small hole
is dug, it fills with water immediately, and cellars are
almost unknown. It was in this quarter that the
epidemic was so severe ; almost all the children were
attacked by it, and a third of them had already died.

Formad went to Ludington to study the epidemic
and collect materials for experiments. In all these
cases of croup, the blood was full of micrococci belong-
ing to Micrococcus diphthericus, some detached, others

216 MICROBES, FERMENTS, AND MOULDS.

united in the form of zoogloea, that is agglutinated in
small masses ; others, again, in the colourless corpuscles
of the blood. .All the organs, and especially the
kidneys, were likewise filled with them.

With the materials gathered at Ludington, Wood
and Formad made some experiments in cultures, and
were able to inoculate rabbits with croup. These
inoculations were made subcutaneously, in the muscles
and trachea, and were followed by the production of
false membranes, and the animals died with all the
symptoms of diphtheria. The blood was full of micro-
cocci. An examination of living animals showed that
the micrococcus first attacked the colourless corpuscles,
within which their vibratile motion could be observed.
The corpuscle changed in appearance, the granules dis-
appeared, and it became so full of micrococci that they
could no longer move : they grew until they caused the
rupture of the corpuscle, and then escaped in the form
of an irregular mass, which constitutes the zoogloea.
Corpuscles filled with micrococci were found in the
false membrane ; in the small vessels, which they dilate
and completely obliterate ; and even in the marrow of
the bones.

Cultures made in flasks afforded important results.
A comparison of the sowings made with micrococci
collected at Ludington with those found in the
ordinary diphtheritic angina, which is common at Phila-
delphia, showed a great difference in the vitality and
virulent properties of microbes derived from these two

THE MICROBES OF HUMAN DISEASES. 217

sources. The former multiplied rapidly and energeti-
cally, succeeding each other up to the tenth generation,
while those from Philadelphia only went to the fourth
or fifth generation, and those taken from the tongue
did not go beyond the third. It must be observed that
the diphtheritic angina of Philadelphia is much less
fatal than croup, and the first attempts at inoculation
made by Formad and Wood produced doubtful results,
precisely because they were made with the microbe
of diphtheritic angina, which is an attenuated form
of the microbe of croup. The organism is the same,
but it is modified by the medium in which it is
developed, and the vitality of artificial cultures is in
direct proportion to the malignity of the disease from
which the germs for sowings are derived.

The following theory may be deduced from these
facts, which will explain all cases of diphtheria : — A
child contracts a simple catarrhal angina, or laryngitis ;
the micrococci, which up to this time remained inert
in the mouth, begin to grow and multiply under the
influence of the inflammatory products which favour
their development ; the plant which has been dormant
becomes widely diffused. There are many degrees
between croup with malignant complications and the
mildest form of diphtheritic angina, as all practical
physicians know. More or less numerous germs of
micrococci float in the air, or — which appeared to be
the case at Ludington — are conveyed in drinking-
"water, and they may encounter more, or less favourable

218 MICROBES, FERMENTS, AND MOULDS.

conditions. If they settle on a child's tender throat,
predisposed for their reception by slight inflammation,
they develop there with frightful rapidity, and
produce croup, and then diphtheria, which is soon
fatal. Nageli calculates that their number may be
doubled within twenty minutes. The plant, of which
the activity is increased by its culture in the person of
one patient, may be expelled with the breath so as
to infect another individual. And just as there are
different degrees of activity in the plant, so the spores
may be more or less contagious, and those of malig-
nant diphtheria are more to be feared than those of
the ordinary diphtheritic angina.

When we consider the remedies to be employed
against the ravages of this cruel disease, it should
first be observed that the only effect of the operation
of tracheotomy, which is successful in barely a third
of the cases, is to admit air into the child's lungs.
Its first curative effect, therefore, consists in saving the
child from the asphyxia by which it is threatened,
and in giving time to apply remedies, but another
explanation is necessary when this operation alone is
enough to effect a cure. Pasteur has shown that pro-
longed contact with the air produces a real attenuation
of virulent microbes. Wood and Formad have estab-
lished similar facts, for when the false membranes of
croup procured at Ludington had been exposed to the
air for several weeks, until they were completely
desiccated, they became perfectly inert, notwithstand-

THE MICROBES OF HUMAN DISEASES. 219

ing their former virulence. They were, however, not
dead, since they were still capable of reproduction, but
only up to the third or fourth generation. It must,
therefore, be admitted that the free access of air given
by tracheotomy, may attenuate the virulence of the
micrococcus of croup.

Too much cannot be said against the misuse of
emetics, which is, unfortunately, very common, since they
are readily administered by parents without medical
advice. A regular emetic of which the action is
much more violent than that of ipecacuanha should
never be given. The micrococci are only found in
the most superficial layers of the false membranes,
and when these are removed, an irritated and bleeding
mucous membrane remains, which had been previously
protected by the false membrane from immediate
contact with the microbes : these now pass without
difficulty into the blood. Thus the ground may be
said to be prepared and rendered more favourable
for the multiplication of the micrococci, which are
sown there afresh, and are reproduced with frightful
rapidity.

The most effectual remedy has been prescribed by
Dr. Fontaine of Bar-sur-Seine. It consists in admin-
istering sulphurous drugs, in the form of sulphate
of calcium, so as to produce in the stomach a
slow disengagement of sulphuretted hydrogen gas,
which checks the development of microbes, or attenu-
ates their virulence. It need scarcely be said that

220 MICROBES, FERMENTS, AND MOULDS.

this treatment must begin at once, before the micro-
cocci have penetrated into the blood. At the same
time a gargle of lemon-juice or citric acid should be
used, which shrivels up the false membranes without
forcibly detaching them. The action of this acid is
explained by the fact that, for the most part, microbes
only thrive in an alkaline medium. By this treat-
ment Fontaine has been able to save nine-tenths of
his patients, while all other modes of treatment
have only succeeded in a third of the cases, and the
proportion is often much smaller.

The first researches made in Europe on the
microbe of diphtheria date from 1873, at which time
Klebs gave an exact description of it under the
name Microsporon diphtericum. In most cases he
observed two forms : micrococci and rods or bacilli.
Struck by the great difference in intensity which the
disease presents in different epidemics, he states in
his later works that there are two kinds of diphtheria,
due to the predominance of one or other of these two
forms, one of which he terms microsporine, and the
other bacillary. The former may be observed in the
east of Europe, and especially in Hungary; while
the latter is more common in Switzerland and the
west, including France. The first is chiefly found
upon the tonsils, and is less serious; while the bacillary
form soon attacks the larynx and trachea, and pro-
duces blood-poisoning, which is rapidly fatal. The
bacilli, which are, like those of tuberculosis, very

THE MICROBES OF HUMAN DISEASES. 221

minute, remain on the surface of the false membranes,
more rarely within them, and on the surface of the
inflamed mucous membrane.

Loffler undertook experiments in culture and
inoculation which confirm Klebs' opinion. He suc-
ceeded in isolating and cultivating separately the
Microsporon, or micrococcus, and the bacillus, which
makes it probable that these are two distinct species.
The chaplets of micrococci, cultivated separately and
used to inoculate animals, do not produce diphtheria ;
the bacilli, on the other hand, cause the formation of
false membranes, but do not exactly reproduce the
diphtheria of the human subject.

Cornil and Babes have likewise studied these two
forms of microbes. They have ascertained that the
bacilli are more generally found in the false mem-
branes of the skin, and the micrococci in those of the
throat and larynx. But in almost all cases they have
found bacilli, zoogloea, and chaplets of micrococci
associated together in the false membranes, even in
those of the skin, and bacilli in those of the throat.

Cornil and Megnin have studied the spontaneous
diphtheria of poultry and domestic quadrupeds. The
anatomical lesions and the form of the microbes
approximate to those of human diphtheria, and cases
of contagion between the calf and man have been
observed. Yet direct inoculation has failed, so that it
is still impossible to affirm the identity of the two
diseases.

222 MICROBES, FERMENTS, AND MOULDS.

We do not think that the dual nature of human
diphtheria, indicated by the researches of Klebs and
Loffler, is yet established. The symptoms, and still
more the histological lesions of this disease, are in
favour of its unity, and it may be owing to other
causes that the disease is more or less severe.

The well-known polymorphism of microbes leads
us to think that the bacilli represent the adult form,
and the micrococci, or Microsporon, the early form of
a single species, which is in all cases the cause of
diphtheria and of its several manifestations — croup,
diphtheria, etc. Further researches are necessary to
decide this question.

Whooping-cough and Influenza. — Burger has
lately discovered rods in the form of an 8 in the
sputum of whooping-cough ; they are found in great
numbers in the white scum, and are even visible to
the naked eye, and, like many other bacteria, they
can be stained by methyl violet. To this microbe
whooping-cough and its relapses are due, and it is
always present. It has not yet been cultivated.

Influenza resembles whooping-cough in the course
it takes, and is probably also caused by microbes.
Letzerich has found micrococci in the blood, to which
he ascribes this disease, but his researches must be
repeated with greater care.

Certain facts observed in medical practice have
led to the surmise that whooping-cough may be re-
garded as an attenuated form of croup, just as vaccinia

THE MICROBES OF HUMAN DISEASES. 223

is an attenuated form of small-pox. The same treat-
ment applies to both diseases. When the patient is
kept in the purifying chamber of a gas manufactory,
where there is a constant disengagement of acid
vapours, sulphuretted hydrogen, hydro-carbons, coal
tar, benzine, carbolic acid, etc., the microbes embedded
in the throat and lungs are attenuated. Sulphate of
calcium is a successful remedy in whooping-cough as
well as in croup.

Children who have had whooping-cough, or who
are passing through the disease, rarely contract croup
even when it is epidemic, although catarrh, inflamma-
tion of the bronchial tubes, ulceration of the mouth,
and general debility, are all predisposing causes of
croup. The question therefore arises whether whoop-
ing-cough does not act as a sort of preventive vaccina-
tion which may serve as a protection against croup.
Further researches and observations should be made
in this direction, if that which we now indicate can
be established as a fact.

XL THE MICROBES OF PHTHISIS AND OF LEPROSY.

These two microbes are so similar in form that it
is necessary to have recourse to chemical reagents and
to staining processes in order to distinguish them
clearly. Both assume the form of an 8, or of slender,
elongated rods, so minute that it is not surprising

224 MICROBES, FERMENTS, AND MOULDS.

that the bacillus should have so long eluded the
observation of the physiologists who have studied the
tubercle of phthisis under the microscope. The form
of both microbes assigns them to the genus bacillus.

The experiments of Villemin, begun ten or twelve
years ago, first showed the parasitic nature of tuber-
culosis, or pulmonary phthisis. Villemin inoculated
rabbits with tubercular matter, showing that the
disease was essentially contagious. More recently
Toussaint and Koch have cultivated the microbe in
a closed vessel, and have inoculated animals with the
produce of the culture ; all these animals died with
symptoms of tuberculosis.

The still more recent researches of Cornil, as he
stated in May, 1883, before the Academy of Medicine,
have confirmed the parasitic nature of this terrible
disease. The microbe has been found in the giant
cells of the tubercle and in the sputum of consumptive
patients ; it has been found in the colourless corpuscles
of the blood, by which it is conveyed into all parts of
the system, and it is also found in all the organs in
which a tubercle can be developed.

The bacillus of tuberculosis is somewhat smaller
than that of leprosy. Each bacillus is from three to
four micro-millimetres in length. They are generally
found associated in the form of chains or chaplets — at
any rate, this is the case in the sputum, as we see in
Fig. 91 A. Koch has cultivated them in gelatinized
blood-serum. Their growth is very slow.

THE MICROBES OF HUMAN DISEASES.

225

Now that this is known, it is easy to explain the
facts of direct contagion which are so frequent among
people living together, and especially from a husband
to a wife, or conversely. Since the breath of a con-
sumptive patient is always charged with germs of
the microbe, which abound in the cavities in which

Fig. 9lA.-Bacilli in the cputum of a consumptive patient: A, bacilli, either isolated
(a) or in the epithelial (6) and pigmented (c) cells of the lung ; B, numerous
bacilli, masked together in the sputum. Stained by Ehrlich's process with
methyl violet (much enlarged).

the sputum is formed, it could not possibly be other-
wise. The following statements of facts are taken from
Debove's clinical lectures at the Hospital de la Pitie.

"Jean, a tuberculous patient, was married to
Antoinette, a young woman with no previous tendency
to tuberculosis. Jean died, and his wife became
phthisical. She was remarried to Louis, who had
likewise no phthisical taint; Louis and Antoinette
both died of phthisis. The niece of the latter, equally
without phthisical taint, contracted the disease in
nursing her aunt, then married, and her husband was

226 MICROBES, FERMENTS, AND MOULDS.

in his turn attacked by phthisis. All these people
resided in a place in which it was easy to verify the
absence of hereditary taint."

Here are other observations of the same nature : —

" A young woman without hereditary taint nursed
a phthisical patient and contracted phthisis. She
returned home, and communicated the disease to the
six sisters with whom she lived. One sister survived,
but she was not living with her family.

" A soldier became phthisical while with his regi-
ment, and was therefore discharged, and returned to
his family. His father, mother, two brothers, and a
neighbour who nursed them, became phthisical. Yet
none of them were predisposed by hereditary taint.

" A girl returned from school in consumption ; on
her death her room and clothes passed to her sister,
who died of the same disease. A third sister died
under like conditions. As their parents still survive,
it is clear that the disease was not due to heredity."

This does not imply that heredity plays no part
in the transmission of the disease, for the contrary is
proved ; yet such transmission often occurs after the
child is born, and sometimes the nurse by whom it
is suckled may be the source of contagion.

In the case of children brought up by hand, the
infection may come from cow's milk which has not
been boiled. Cows are often attacked by tuberculosis,
and numerous bacilli have been found in the teats and
milk of these animals. This indicates the necessity

THE MICROBES OF HUMAN DISEASES. 227

of boiling the milk used for food, especially in the
case of children, at any rate when the source is un-
known.*

Phthisis is, as we know, a slow disease, probably
because the microbe is anaerobic, and lives within the
cellular tissue, not in the blood, which it merely tra-
verses. The slow progress of the disease explains the
cases of spontaneous cure effected by the expulsion of
the microbe in the sputum, or by the tubercles passing
into a cretaceous condition, which causes the destruc-
tion of the bacteria encysted in them. Hence also
the fact that all the causes which weaken the consti-
tution, bad food, overwork, inflammatory diseases,
pregnancy, etc., hasten the end of consumptive per-
sons. Those who are attacked by the disease may,
if rich enough to live in the South, and to follow
with care the hygienic prescriptions of the physician,
often attain an advanced age, in spite of the lesions
which remain latent in the organism, provided also
they commit no imprudence in the matter of diet.

It is therefore important to maintain the strength
of consumptive patients by tonics, by a nourishing diet,
and by an hygiene as strictly protective as possible.
The good effects of creosote, of sulphur waters, etc.,
are due, as in diphtheria, to the attenuation of the

* This precaution is equally efficacious to ward off typhoid fever.
In several epidemics of this disease, and especially in England, inquiry
has shown that miik was the vehicle of contagion, either from the
water with which it was adulterated, or from that which was used
to wash the vessels in which it was placed.

228

MICROBES, FERMENTS, AND MOULDS.

virulent properties of the microbe. Hansen considers
that alkalis, not acids, are the best antiseptics in this
disease.

Tubercular leprosy, termed elephantiasis by the
ancients, is caused by tubercles seated in the skin,
and containing a bacillus greatly resembling that of
phthisis, but larger (Fig. 92). This microbe is anae-

Fig. 92.— Bacilli of leprosy, encysted in the subcutaneous connective tissue of the skin
(much enlarged).

robic, and can only live in the dermic cells, in which
it is encysted. Hence the treatment which experi-
ence, preceding the theory, showed to be the most
efficacious : instead of keeping the ulcers covered, they
should be exposed to the air and sun, often washed,
and kept as clean as possible. This disease, which is
essentially contagious, is very rare in Europe, but
common in Egypt and throughout Asia.

THE MICROBES OF HUMAN DISEASES. 229

XII. THE MICROBE OF PNEUMONIA.

One of the most important micrographic dis-
coveries of late years is that a microbe is always
present in inflammation of the lungs, or pneumonia.
This disease was long considered, and is still con-
sidered by the majority of doctors, to be altogether
independent of any parasitic infection. It is such
a matter of tradition, both among patients and their
doctors, to ascribe this disease to accidental causes,
and especially to a sudden chill, that the parasitic
doctrine of pneumonia at once encountered a lively

Fig. 93. — Micrococci in sputum of pneumonia : b, d, free, or encysted in the lymphatic
cells a, c ; n, nuclei of cells (much enlarged).

opposition. It is, however, now impossible to deny
the important part taken by microbes in the trans-
mission of this disease.

The microbe of pneumonia was discovered by
Friedlander and Talamon in 1882. It consists of
micrococci, often associated in an 8 or in short chains
(Fig. 93), and found in the sputum and lungs of
pneumonic patients, either detached or encysted in the
lymphatic cells.

230 MICROBES, FERMENTS, AND MOULDS.

Under a strong magnifying power, this micrococcus
is seen to be shaped like a lance-head, and short rods,
terminating in a cone, are found with it. It is probable
that the micrococcus is the early form of the microbe,
which becomes a bacillus in the adult form (Cornil).

The presence of a microbe in pneumonia explains
many facts which had remained obscure in this
disease, especially the epidemics in a room or house,
when several persons living together are successively
attacked by pneumonia. It likewise explains the
resemblance, which has long been indicated by their
common name, between the pneumonia of man and
the contagious pneumonia of cattle, which is well
known to be essentially epidemic, transmissible by
contact and inoculation.

A culture of the microbe of pneumonia can be
made, and when it is inoculated into the tissue of the
lung, it produces in animals a true pneumonia.

XIII. SOME OTHER DISEASES CAUSED BY MICROBES.

We shall only say a few words about several other
diseases, admitted to be contagious, and in which the
presence of a special microbe has been ascertained.

In the pus-corpuscles of gonorrhoea, very minute
and mobile inicrococci may be observed, often associated
in pairs, in fours, or in a small mass, but rarely in
chaplets (Fig. 94).

THE MICROBES OP HUMAN DISEASES. 231

The same micrococcus, or, at any rate, a microbe
which cannot be distinguished from it, is often found
in the purulent ophthalmia of new-born infants. It
is difficult to admit, even when we make allowance
for the great susceptibility of an infant's eyes at the
moment of birth, that such ophthalmia is always of
gonorrhoeal origin. However this may be, the
micrococci of purulent ophthalmia resemble those of
gonorrhoea, and the same treatment is applicable.
The solution of nitrate of silver in a diluted form,
generally employed in maternity hospitals, as a pre-

Fig. 94. — Cells of gonorrhoeal pus 2* hours after its discharge. Within may be seen
several forms ol fission of their nuclei, and micrococci moving in the protoplasm
(X 600 diam.).

ventive treatment of infant ophthalmia, has con-
siderably reduced the intensity of this disease

The red, malodorous sweat of the armpits is due
to the presence of a microbe, which is found free in
the sweat, or massed in the form of a zoogloea, and
adherent to the hair of the skin. The red colour is
not due to iron, for no trace ofi this metal is revealed
by analysis ; it approximates in its nature to that of
Micrococcus prodigiosm. It may be cultivated in

232 MICROBES, FERMENTS, AND MOULDS.

white of egg at a temperature of 37°, in which it
retains its characteristic colour.

In a sweating foot, of which the smell is so
offensive, Rosenbach found a short, thick rod, which
is at once aerobic and anaerobic, is rapidly developed,
and retains its offensive smell when cultivated (Fig. 95).

In the gangrene of long bones, the same observer

Fig. 95.— Bacillus of Fig. 96.— Saprogenic bacillus

feet-sweat. of osseous gangrene.

has found a similar bacillus, which, like the foregoing
one, produces by inoculation a local affection, more or
less strongly marked (Fig. 96).

Warts. — We know that a wart is self-sown, and
appears to contain a contagious principle. This is
Tomasi Crudeli's Bacterium porri, and is minute and
in the form of an 8.

Among the diseases due to microbes we must
include mumps, epidemic goitre, epithelial xerosis of
the eye, polypus of the nasal canal, of which the
concretions are formed of Streptothrix Forsteri, etc.

XIV. THE MICROBE OF ERYSIPELAS.

Erysipelas belongs both to internal and external
pathology. It is sometimes manifested as a special

THE MICROBES OF HUMAN DISEASES.

233

primary disease, characterized by the inflammation of
the skin, and sometimes as a secondary complication
of wounds, sores, and surgical operations. In any case,
the course taken by the disease and its contagious
nature enables us to assume the presence of a microbe.
Martin, Volkmann, and Hiiter found bacteria in the
patches of skin ; and Hayem found them in the pus of
meningitis, "which followed erysipelas of the face.
Lukomski was able to inoculate rabbits with the
disease, which may also be communicated by vaccine
lymph, taken from a child suffering from erysipelas.
Fehleisen has cultivated the microbe in a pure state,

Fig. 97.— Section of the skin in erysipelas : the interfascicular space (e) is full of
microbes (m) in 8's or chains; t, connective tissue (x 600 diam.).

and has inoculated man with it, always reproducing
erysipelas with its characteristics and typical course.
Antiseptics, such as carbolic acid and analogous sub-
stances, employed either as outward applications or as
subcutaneous injections, have been successful in many
instances in arresting the development of the disease.

Erysipelas serves as the transition to those diseases
within the domain of surgery, and which are generally
due to sores, wounds, and operations.

234 MICROBES, FERMENTS, AND MOULDS.

XV. MICROBES OF Pus; PY^MIA AND SEPTICAEMIA.

Sores and surgical operations are often followed
by a general poisoning of the blood and of the whole
system — a severe affection which is rapidly fatal, and
characterized by the presence of pus-corpuscles in con-
siderable numbers in the blood and in the principal
organs. Together with these pus-corpuscles there is
always a special microbe, termed Micrococcus septicus,
which, like that of diphtheria, may either appear free
or in the form of chaplets (vibrio), or in the interior
of the colourless corpuscles of pus, or embryonic cells,
of which it effects the rupture in the form of zoogloea.

This microbe, or others of
allied species, are the im-
mediate cause of that poison-
ing of the blood which is
termed pyaemia, septicaemia,
traumatic fever, puerperal
fever, post-mortem wounds,
etc. The germs of Micro-

Fig. 98.— Pus-corpuscles of puerperal

chlin°8n(xs'8ooudiamf) ^^^ coccus septicus are intro-

duced into the blood, and

multiply there, through the exposed surface of a wound,
or sometimes by means of the instrument which caused
it (Fig. 98).

When the instrument causing the wound is charged
with microbes, it is not necessary that the wound

THE MICROBES OF HUMAN DISEASES. 235

should be gaping : there is in this case a true inocula-
tion. Such is the case in a post-mortem wound. The
experiments of Tedenat, of Lyons, show that when
decomposition has not begun in the corpses of healthy
persons, who have died by violence, the autopsy pre-
sents no danger ; but this is not the case when death
is due to an infectious disease, pyaemia, erysipelas, etc.
On the other hand, the puncture will have no evil
results if the bleeding is profuse, or if the microbes
and their germs have been removed by immediate
suction. Some hours after death, all corpses contain
microbes, which have penetrated into the blood owing
to the softening of the tissues, and which either come
from the external air or from the digestive canal.

The enormous number of pus-corpuscles which
appear in a very short time in the blood was for a
long while a problem for physicians. It is now known
that these corpuscles have their source not only in the
wound, but also in all parts of the vascular system,
and especially in the capillaries, according to Schiff s
theory. The microbian theory may easily be made
to agree with the latter, and Sternberg was the first
to suggest that it appears to be the function of the
colourless corpuscles to take possession of the bacteria
introduced into the blood, and to destroy them. We
know, in fact, that the colourless corpuscles do take
possession of all foreign particles, such as micrococci and
bacteria, introduced into the blood, and in some sense
encyst them in their protoplasm. When these bacteria

236 MICROBES, FERMENTS, AND MOULDS.

multiply in the blood, they must necessarily have an
irritating effect on the walls of the blood -capillaries
and this appears in the swelling of the cells and their
return to the spherical form ; in a word, they are
transformed into embryonic or migratory cells (accord-
ing to Cohnheim's theory). These do not differ, or
only differ slightly, from the colourless corpuscles of
the blood, and are pus-corpuscles. This new theory
is in accordance with the facts daily presented to us
in the treatment of surgical diseases.

XVI. MICROBES OF SOME OTHER DISEASES, RESULTING
FROM WOUNDS.

Whitlow and Agnail. — These two complaints are
produced by pricking the finger with some instru-
ment charged with microbes. Chains of bacteria or
micrococci are always found in the collection of pus
or serous discharge.

Soil and Carbuncle. — The pus from a boil contains
micrococci, which Pasteur first observed, and which he
has cultivated in an infusion of yeast and in chicken-
broth.

It was found by Rosenbach in osteomyelitis, and
was termed by him Staphylococcus pyogenus aureus
(Fig. 99).

Carbuncle only differs from a boil in its larger
size, and contains the same microbe. It is well known'

THE MICROBES OF HUMAN DISEASES. 237

that it is readily and spontaneously self-inoculated,
and that boils and carbuncles rarely occur singly
in the same individual. Diabetic
patients are very subject to this

affection, yet the microbe does not "*

Fig. 99.— Boil microbe

admit of culture in sugared water. (staphyiococcui n/o-

genus aurtus: Rosen-

Phlegmon. — This is the name given bad')-
to the suppuration of the subcutaneous cellular tissue,
caused by contusions, wounds, and medical injections
of morphia or any other sub-
stance. Microbes are always
found associated in 8's or in
long sinuous chains
100). In all these cases
has been some communica-
tion with the outer air, for
wounds which are really sub-
cutaneous — fractures, for ex-

<*r>nnm Fig. 100.— Pus of phlegmon, contain-
aCCOm- ing chains of micrococci (x 1000

panied by abundant haemorr-

hage, heal without suppuration, and microbes are not

present.

XVII. MODE OF ACTION OF MICROBES IN DISEASE.
PTOMAINES.

The question how microbes act in disease has long
been doubtful, but the progress of science tends to
clear away obscurity.

238 MICKOBES, FERMENTS, AND MOULDS.

The first idea was that microbes introduced into the
blood or tissue of an animal acted like parasites of
a higher organism — intestinal worms, for instance — by
deriving their nourishment from their medium, and
developing at its expense. It is evident that this
must be the case, and that in anthrax, or splenic fever,
for example, the bacilli which swarm in the blood
abstract from the red corpuscles the oxygen they
require, and thus produce asphyxia and the death of
the animal.

Yet it often happens, even in anthrax, that death
is so rapid, that the bacilli have not yet had time to
develop in the blood in numbers sufiicient to produce
such fatal effects. So, again, in cholera, the comma
bacillus has not yet been found in the blood, and yet
cases of sudden death are not uncommon in this
disease. Some other explanation is therefore required.

Panum first showed, from the study of the pro-
ducts of putrefaction, that a poisonous substance,
resembling snake-venom and vegetable alkaloids, is
developed as the ultimate product of the putrid fer-
mentation of organic matter. Twelve milligrammes of
this substance kill a dog, while neither ammonia nor
the acids which are first formed in this fermentation can
produce septicaemia. Bergemann and Schmiedeberg
have termed this poisonous substance septine.

Panum's researches have been recently resumed by
Selmi and Gautier, who have extracted from corpses
and putrefying organic matter a certain number of

THE MICROBES OF HUMAN DISEASES. 239

poisonous substances greatly resembling vegetable
alkaloids, and termed by them ptomaines.

The action of ptomaines may be compared to that
of strychnine. Injected into the blood, even after
the removal of every living microbe, the ptomaines
produce fever, rigors, vomiting, diarrhoea, spasms,
torpor, collapse, and finally death. It is probable that
in some cases of poisoning by tainted meat or fish
their poisonous properties are due to the presence of
ptomaines.

But in all cases these ptomaines are shown to be
the product of putrid fermentation, which is always
effected in dead bodies by special microbes. Here the
ptomaines are due to the work of the microbes of
putrefaction, and are made by them, just as alcohol
and the carbonic acid of alcoholic fermentation are
made by yeast, at the expense of the sugared liquid
in which they live and multiply.

Direct experiments show that when septine, from
which every microbe has been removed, is injected
into the human subject, it produces feverish disturb-
ance, but only causes death when introduced in con-
siderable quantities. If, on the other hand, there is
in the same individual a large suppurating wound,
exposed to the air instead of being covered by an air-
tight dressing, a purulent infection (septicaemia) will
almost certainly ensue, since the microbes introduced
by means of this wound will find in it a favourable
soil (pus and putrefying organic matter); they will

240 MICROBES, FERMENTS, AND MOULDS.

multiply in immense numbers, and manufacture of
these materials a great quantity of septic poison, at the
expense of the organism in which they are developed.

It is now admitted that the chief action of patho-
genic microbes, or, at any rate, of the most dangerous
among them, consists in the ptomaines which they
secrete within the body. This explains why death by
cholera is so rapid and even sudden, when the comma
bacillus is still only found in the intestines. Although
this micro-organism has not been absorbed by the
intestinal mucous membrane and carried into the
blood, the poisonous alkaloid, or ptomaine, which it
secretes is certainly present, and to this the nervous
symptoms, such as cramp, etc., which characterize this
disease, may probably be ascribed.

Pouchet has extracted from the fseces of choleraic
patients, a special alkaloid of the nature of ptomaine ;
and quite recently, in August, 1885, he has found traces
of the same alkaloid in infusions of pure culture of
Koch's comma bacillus.*

In conclusion, at the present stage of our know-
ledge, it may be admitted that the action of patho-
genic microbes on the system is complex, and may
be analyzed as follows : — (1) The action of a living

* This affords the germ of the idea of a new process for preparing
lymph, which has perhaps already been put in practice. A Spanish
physician states that the secret process employed by Ferran simply
consists in filtering his culture infusion by means of the Chamberland
filter, and using this liquid for inoculation, since it contains the
ptomaine of cholera without its bacillus (?).

THE MICROBES OF HUMAN DISEASES. 241

parasite, which is nourished and multiplies at the
expense of the fluids and gases of the system ; (2) the
formation by this parasite of a poisonous substance
(ptomaine), of which the elements are derived from the
organism, and it acts as a poison on this organism.

242 MICROBES, FERMENTS, AND MOULDS.

CHAPTER VI.

MEANS OF DEFENCE AGAINST MICROBES.

I. ANTISEPTIC TREATMENT OF WOUNDS: GU^RIN'S
PROTECTIVE DRESSING; LISTER'S DRESSING.

THE first and most brilliant application of the theory
of microbes to human therapeutics has been made in
the treatment of wounds.

Since it is admitted that the danger of a wound
or of a surgical operation is chiefly due to the contact
of the wound with the external air, which is laden
with germs, or with the dressing which may contain
microbes, all the surgeon's efforts should be directed
to preventing such contact. This may be accom-
plished by several processes, now generally employed
by surgeons, and these may be regarded as the noblest
achievement of modern surgery.

In Guerin's protective dressing, this skilful surgeon
has made a practical use of Tyndal's and Pasteur's
researches into the nature of air-germs» We have

MEANS OF DEFENCE AGAINST MICROBES. 243

already said that air filtered through a sufficiently thick
layer of cotton wool becomes free from germs. Guerin
covers that part of the body in which the wound is
situated with several layers of cotton wool, carefully
applied and confined by a cotton bandage. This
dressing permits the access of air to a certain extent,
but the air is filtered through the cotton wool, which
arrests all microbes ; and this is proved by removing
the dressing after the lapse of several days, when the
wound will be found to be in a satisfactory state, and
in process of healing. A certain amount of pus is
produced, but much less than in the old-fashioned
lint dressing, and this pus is not putrefied, since the
germs which are the agents of putrefaction have
been excluded.

The English surgeon, Lister, has arrived at the
same result by a more complicated process, which
has, however, been generally adopted in France. His
process is based on the use of carbolic acid as an
antiseptic or destructive agent of microbes and germs.
Whenever an operation is to be performed, the instru-
ments, the surgeon's hands, those of his assistants,
and all the materials used for dressing, must be
steeped in a sufficiently dilute solution of carbolic
acid ; throughout the operation the wound must be
surrounded with a spray of the same solution, playing
over the hands of the surgeon and over all he touches.
The same solution and the same precautions are
applicable to the treatment of all wounds, whatever

244 MICROBES, FERMENTS, AND MOULDS.

be their origin, and should be renewed whenever the
wound is dressed.

We cannot describe Lister's dressing in detail, but
will only mention — (1) that the skin surrounding the
region of the operation, the surgeon's hands, and the
instruments are washed with a carbolic solution of two
to three per cent. ; (2) the spray contains one per cent,
of carbolic acid ; (3) the ligature of the arteries is done
with carbolized catgut, which is eventually dissolved
in the wound ; (4) the drainage-tube usually arranged
for the outflow of the discharge is likewise carbolized ;
(5) so also are the eight folds of gauze, which is
used instead of linen dressings ; (6) a protective, con-
sisting of green oiled silk, steeped in carbolic acid
and varnished like court-plaister, is interposed to
prevent the irritating effect of the gauze on the
wound ; (7) an impermeable mackintosh, laid between
the seventh and eighth folds of gauze, prevents the
penetration of fluids.

The admirable results obtained by Lister's method
are the strongest confirmation of the truth of the
theory of microbes. Since its introduction into
medical practice, mortality among the wounded and
among the surgical patients has considerably diminished,
and operations formerly considered impracticable have
been undertaken and successfully carried out.

Carbolic acid is not the only antiseptic which
affords excellent results by destroying, or at all events
by attenuating, the virulence of microbes and their

MEANS OF DEFENCE AGAINST MICROBES. 245

germs. Alcohol, which has been long in use, boracic
acid, salicylic acid, thymol (essence of thyme), and
eucalyptol (the essence extracted from Eucalyptus
globulus), and many other substances, have been
employed both internally and externally with this
object, and most of them take a more or less impor-
tant place in the therapeutics of those diseases caused
by microbes.

IL HYGIENE OF DRINKING-WATER: WATER FREE
FROM MICROBES ; CHAMBERLAND FILTER.

The researches carried on by Miquel for some years
at the Observatory of Montsouris, at the Pantheon,
and in other parts of Paris, teach us that living
bacteria are more rare in the atmosphere than had
been generally supposed. We have already said that
air is the great purifier of microbes, which it destroys
by desiccation. Even in the infection of wounds, it
is probable that the liquids and linen formerly
employed for dressings transported the microbes in
greater number than the air, however charged it
might be with these organisms in the neighbourhood
of a hospital.

In the water which supplies large towns, whether
furnished from wells or streams, a large number of
microbes are, however, found in a state of perfect vitality.
This is quite natural, since we know that these plants

246 MICROBES, FERMENTS, AND MOULDS.

cannot exist without moisture, and they find in such
water the organic matter which nourishes them. The
rivers receive them by the sewers which discharge into
them, the wells by infiltration of the soil, and thus
in times of epidemic, the microbes of typhoid fever
and of cholera are always to be found in running or
stagnant waters, which therefore become the vehicle
of infectious diseases.

Well-water, owing to its stagnant nature, and to
the infiltration to which it is liable from cesspools
which are often leaky, is more dangerous than
running water. About two years ago, an epidemic
of typhoid fever, which occurred in one quarter of
Angers, was stopped by introducing a supply of water
from the Loire ; up to that time well-water had been
exclusively in use.

Well-water in Bread-making. — In many places
well-water is still too often used for making bread
instead of running water. There are probably many
reasons for this preference. Bakers, without assigning
any reason for the fact, assert that well-water causes
the bread to rise better ; and moreover, in towns, such
as Angers, where there is a water company, river-
water costs money, while well-water may be had for
nothing. About 50 per cent, of water is used in
making bread, which explains the preference shown
by bakers for well-water, and also the importance
ascribed by hygienists to the purity of the water
used in bread-making.

MEANS OF DEFENCE AGAINST MICROBES. 247

In fact, direct experiments, made with a maximum
registering thermometer enclosed in the dough, shows
that the internal temperature of the loaf, that of the
crumb, rarely rises to 100°. We know that this tem-
perature does not suffice to destroy most microbes,
still less their germs, for which a temperature of from
115° to 160° is necessary.

In 1884, Bouvet, a chemist, and Preaubert, a pro-
fessor at the Lycee, were commissioned by the munici-
pality of Angers to make a microscopic examination of
numerous specimens of well-water used by bakers in
their trade in different parts of the town. The exami-
nation of deposits, either obtained spontaneously by
allowing the water to stand for twenty-four hoflrs, or
by testing the water with osmic acid, in accordance
with Certes's process, almost invariably revealed the
presence not only of the ova of ascarides, but of
numerous microbes — some of them harmless, like
Bacterium termo ; others doubtful, on account of their
forming chains like the micrococcus (two species of
different form), and resembling Micrococcus diphthe-
ricus. Now, croup may be regarded as endemic at
Angers. In four wells out of the twenty-five ex-
amined these microbes were found in great numbers.
It must be noted that micrococci are not found in
strongly aerated water, but only in that of which
the organic deposit is abundant.

Well-water must, therefore, be generally condemned,
both for drinking purposes and for the making of

248 MICROBES, FERMENTS, AND MOULDS.

bread. Spring- water, and still more river-water, as
it is now supplied in towns by a system of pipes,
is not free from organic matter, nor from microbes,
although they are less abundant than in well-water.
Purification is therefore necessary.

With this object, it is recommended, especially in
times of epidemic, to boil the water, so as to destroy
the microbes contained in it. But this process expels
the gases, and reduces the proportion of salts in solu-
tion, thus rendering the water heavy and indigestible.
It has, therefore, been suggested that only weak
mineral waters should be drunk, such as that of
Saint Galmier, which, if taken at the source and
immediately placed in hermetically sealed bottles,
contains very few microbes. But this process is
costly, so that only rich people can avail themselves
of it. The most practicable mode of purifying table-
water and rendering it wholesome is by the use of
filters.

Ordinary Filters. Charriberland' s Microbe Filter.
— Every one is acquainted with the common filter,
made with crushed sandstone, charcoal, etc., which
should be found in all households and kitchens. This
generally suffices to free water from organic matter,
and especially from the ova of ascarides (intestinal
worms), which, when introduced into the system,
develop and cause inconvenience to so many children,
and even to grown persons. It is impossible to insist
too strongly on the fact that the presence of ascarides

MEANS OF DEFENCE AGAINST MICROBES. 249

in the intestines is always due to the use of unfiltered
water, and this should enforce the general use of
filters, which is often neglected even by those who
cannot be deterred by the relatively moderate cost
of an instrument which it is almost impossible to
wear out. An ordinary filter, however, can arrest a
very small proportion of microbes, which are much
more minute than the ova of ascarides.

A filter has, therefore, been devised, so perfect as
to allow the passage of no solid matter in suspension,
not even the most minute organisms contained in
drinking-water. This result is effected by the filter
invented by Chamberland in Pasteur's laboratory.
The filter is formed (Fig. 101) of a vessel of biscuit-
ware, A, shaped like a candle (whence its name of
bougie Chamberland) ; this is fastened to the lower
part of the metallic receiver D, which receives under
pressure the water coming from the cock E. This
vessel consequently filters the water from without to
within, and it flows through the orifice B, perfectly
free from solid particles, as it appears from a micro-
graphic examination.

Fitted to the distributing water-taps of many
houses in Paris, and especially in lycees, the Cham-
berland filter acts under the normal pressure of the
water-conduit, and, by a new modification of the
inventor, can even act without such pressure. For
this purpose he arranges his filters in a battery, from
eight to ten or more, in a cylindrical receiver, closed

250 MICROBES, FERMENTS, AND MOULDS.

in its upper part. This receiver is connected by a
caoutchouc tube with the vessel which contains water

Fig. 101.— Section and elevation of Chamberland's filter.

for filtering. When the vessel is placed two or three
metres above the filter, from fifteen to twenty litres

MEANS OF DEFENCE AGAINST MICROBES. 251

of perfectly pure water may be obtained in the course
of an hour. Under the pressure of the taps of the
Paris water-supply, the jet of the filtered water is
as strong as that of the pipes used for watering our
gardens; in fact, it gives out four or five litres a
minute under the pressure of two or three atmospheres.

Preservation of Alimentary Substances. Appert's
Protective Process, etc. — We have already said that
organic substances may be preserved unchanged for
an indefinite time, as long as they are protected from
the microbes and germs in the air. This was shown
by Pasteur's exhaustive experiments. He took urine
and blood, and transferred them directly from the
animal organs into glass flasks which had been pre-
viously sterilized or deprived of all germs. These
flasks were hermetically closed and kept for forty-five
days. When opened at the end of that time, it was
ascertained that the smell and appearance of the
liquids were unchanged, that no putrid gas had been
developed, and even that some of the oxygen in the
flasks had not been absorbed.

Most of the processes in use, even before this
experiment, for the preservation of food substances,
are only the practical application of this principle :
the exclusion of microbes and germs.

Appert's process, now so generally used to preserve
meat and vegetables, consists in enclosing the sub-
stances to be preserved in tins, which are hermetically
closed, and heated to a temperature of 110°, so as

252 M1CKOBES, FEKMENTS, AND MOULDS.

to ensure the destruction of all germs. A very small
aperture is left at the top of the case for the escape
of steam and air, which is closed with a drop of solder
before the ebullition of the liquid within is completely
over.

The envelopment of meat in its own fat, its pre-
servation in sugar, wax, etc., are analogous protective
processes, always employed at a high temperature.

When meat is smoked, the aromatic principles of
carbolic acid, creosote, etc., contained in the smoke,
destroy the ferments and prevent the subsequent
development of air-germs. It is, therefore, a true anti-
septic, analogous to the salts used to preserve meat
or fish by pickling. Meat may also be preserved by
desiccation, when it is cut in thin strips and exposed
to the sun and air. This constitutes the jerked beef
of South America.

Excellent results are now obtained by drying meat
at from 35° to 55° in a stove through which a current
of dry air is passed. The powdered meats to be ob-
tained from chemists, which are of great use in nourish-
ing the sick and convalescent, are prepared by an
improvement on this process. They are absolutely
free from smell, and will keep as long as they are
protected from damp. Vegetables cooked by steam,
and then compressed and dried, may be kept for
several years.

Refrigeration by ice has been used to preserve
meat. But when congelation has occurred in the

MEANS OF DEFENCE AGAINST MICKOBES. 253

fluids contained in the muscular tissue, putrefaction
sets in, and rapidly increases, as soon as the tempera-
ture rises a few degrees above freezing-point. The
meat also acquires an unpleasantly sweet taste. It
will be remembered that the first cargo of frozen
American meat which was brought to Paris had con-
tracted an unpleasant taste and was very soon
tainted. When meat, game, or fish is kept in ice, the
congelation of the fluids contained in their tissues
must therefore be avoided.

Many antiseptics, vinegar, alcohol, glycerine, etc.,
may likewise be used to preserve meat and other
alimentary substances.

Antiseptics and Disinfectants. — We will discuss
the substances which are thus designated, especially
from the hygienic point of view, and as a preventive
treatment of contagious diseases, indicating the action
of these substances on microbes.

Antiseptics have been studied by Jalan de La Croix
with reference to their action on microbes in general.
His experiments were performed on culture liquids
made of the juice of cooked meat, into which he
introduced an equal number of drops of the same
broth, which contained fully developed bacteria. He
next ascertained the dose, in milligrammes, of an
antiseptic substance which would suffice either to
arrest their multiplication or to destroy the microbes,
and consequently to sterilize the liquid.

254 MICROBES, FERMENTS, AND MOULDS.

He analysed in this way twenty substances con-
sidered to be antiseptic, or commonly used as such.
He has published a table in which these substances
are classified in their order of activity, and it includes
among others the following antiseptics, which we cite
in the order assigned to them : —

Corrosive sublimate (mercuric chloride) No. 1

Chloride of lime at 98° No, 3

Sulphurous acid No. 4

Essence of mustard No. 9

Thymol No. 13

Salicylic acid No. 14

Carbolic acid No. 16

Boracic acid No. 18

Alcohol No. 19

Essence of eucalyptus No. 20

The three last substances are incapable of steri-
lizing culture broths.

This table shows that carbolic acid, which is now
so much in use, does not destroy microbes so efficiently
as salicylic acid, permanganate of potassium, thymol,
benzoic acid, bromides, and iodine. In this estimate,
however, we must take into account how far the use
of each antiseptic is practicable.

Thus, corrosive sublimate, which these experiments
show to be the best antiseptic, can be used as an
external lotion, but it cannot be given internally in
doses sufficient to produce the desired effect. Eighty
milligrammes are required to sterilize a litre of broth,
and forty to arrest the development of bacteria.
Twenty milligrammes will not effect this result, and

MEANS OF DEFENCE AGAINST MICROBES. 255

this latter dose is a maximum which it is almost
impossible to exceed in man in the course of twenty-
four hours without poisoning him.

Sulphurous acid is very effectual when employed
in fumigations, but it does not penetrate to the interior
of the tissues, and only acts on the microbes on their
surface. It does not destroy their spores.

Iodine has great effect in this respect. Davaine
has ascertained that seven milligrammes of iodine
suffice to destroy the bacteria of anthrax in a litre
of liquid. Instead of a hot iron, tincture of iodine
might, therefore, be used to cauterize the bites of
poisonous flies, carbuncles, and the pustule of anthrax.

Koch states that a solution of five per cent, of
carbolic acid is required to destroy the spores of
anthrax in twenty-four hours ; but the bacilli them-
selves are destroyed by a solution of one per cent.
A solution of 0 02 per cent, iodine, or 007 per cent,
of bromine prevents the development of bacilli.

Chloride of zinc and sulphate of iron, which have
been recommended as disinfectants, are very inferior
to chloride of lime, which takes the third place in the
list, the second being occupied by chlorine.

Alcohol arrests the development of bacteria and
their spdres, but does not destroy the latter, even
at the end of a month, as it is stated by Claude
Bernard.

Babes regards essence of mustard as an excellent
preservative from cholera. If a drop of this essence

256 MICKOBES, FEKMENTS, AND MOULDS.

is put at the bottom of a bell-glass which covers a
culture of comma bacilli, it arrests their development
and destroys them within forty-eight hours.

When cholera is epidemic, it has been suggested
that rum or cognac should be taken, to which salicylic
acid is added, in the proportion of 25 grammes to the
litre. A petit verre, or three teaspoonsful, of this mixture
may be taken between meals in coffee, tea, or grog.

Redard has been recently occupied with the dis-
infection of the railway-waggons used for the trans-
port of cattle. He regards most of the substances
employed, including sulphurous acid, as insufficient.
The only effectual process is by steam, at a tempera-
ture of 110°, which may be easily procured at the
railway stations.

As we have already said, the oxygen contained in
air is an excellent antiseptic, and the attempt has
been made to employ it ; but the experiments of Bert
and Regnard show that bacteria are only destroyed
by oxygen at a high pressure. As for oxygenated
water, it has not yet afforded the results which were
expected from it.

Finally, each species of microbe appears to be
more or less sensitive to the action of different
therapeutic agents. Thus the effect of mercurial salts
on the microbe of syphilis was known before the
existence of the microbe itself was known ; that of
the salts of quinine and arsenic on the microbes of
intermittent fever, etc.

MEANS OF DEFENCE AGAINST MICKOBES. 257

We must, in conclusion, rely much more upon
measures of hygiene than on antiseptics to ward off
the attacks of the microbes which are factors of
disease. Even in Lister's dressing, it is probable
that the hermetic closing of the wound has, as it is
shown by Gue"rin's process, much more effect than
carbolic acid, which is shown by direct experiments
to be a feeble and generally an insufficient antiseptic.

We have still to speak of the preventive vaccina-
tions and inoculations on which medicine relies more
than on antiseptics; but this subject will be better
discussed in the ^following chapter, when we have
spoken of the processes of culture by which the
liquids destined for these inoculations are prepared.

258 MICROBES, FERMENTS, AND MOULDS.

CHAPTER VII

LABORATORY RESEARCH, AND CULTURE OF MICROBES.

THE processes employed in laboratories" for the study
and culture of pathogenic microbes are now very
complicated, and they have attained a remarkable
degree of perfection. In such an elementary work as
this we can only give a general idea of these different
processes, and for details we must refer our readers to
the valuable work by Cornil and Babes, Les Bacteries,
in which the technique of laboratories devoted to the
histology of microbes is described with great accuracy
and clearness.

Microscopes. — The best instruments for the research
and study of microbes are those of Zeiss, Jena, and
Ve'rick, Paris. Immersion lenses, either for use in
water or in other homogeneous liquids, are indispen-
sable for the high magnifying power which is necessary
in order to see most bacteria distinctly. Condensers,
especially those of Abbe', made by Zeiss, are no less
useful in order to concentrate the luminous rays on
that point of the preparation which is to be specially
examined, and to place the bacteria in relief after

LABOEATORY RESEARCH, ETC. 259

they have been stained by the process we are about to
mention.

A preparation ought first to be examined under a
low magnifying power (from 50 to 100 diameters), so
as to study the topography of the object, and ascertain
the points at which the colonies of microbes may be
sought amid the tissues of a section, or of the matters
in suspension in the liquid.

We should then go on to a higher magnifying
power (for example, to from 500 to 700 diameters),
making use of the simple light of the mirror ; and we
should ultimately come to the highest magnifying
powers (from 1000 to 1500 diameters), using immer-
sion-lenses and the condenser.

Instruments, Microtome. — The instruments for fine
dissection are those commonly used in histology. In
addition, needles of glass and platinum are necessary,
and thin spatulas of nickel to convey the sections, etc.

The ordinary razor, which serves for hand sections,
will not do for the thin, wide sections necessary for
the discovery of bacteria. In this case a microtome
must be used, an instrument for making thin sections,
for which purpose those of Thoma or Verick are the
best. Sometimes the object to be examined is
hardened by freezing it with ether spray, since this
makes it possible to cut thin sections by hand. This
is Jung's process.

Non - staining Liquid Reagents. — Acids, bases,
alcohol, oil of aniline, and other essences serve to

260

MICROBES, FEKMENTS, AND MOULDS.

dehydrate and partially decolourize preparations,
Canada balsam is used to mount them; and finally
distilled water, absolutely free from microbes, which
may be easily obtained by means of the Chamberland
filter already described, is used for washing instru-
ments, etc.

Mode of collecting the Liquids to be examined. — In
order to collect the liquids to be obtained
in the wards of a hospital or elsewhere
(blood, urine, sputum, stagnant or sewer
water, etc.), pipettes, which may be either
straight or with twisted necks, are used,
ending in a capillary point closed by
heat, and in its upper part by a stopper
of fine, sterilized cotton wool. The
pipette is heated at a blowpipe flame,
in order to destroy the germs. When it
is to be used, the point is broken off',
and it is plunged into the liquid (dis-
charge from a freshly opened abscess,
blister of erysipelas, etc.), and an aspira-
tion is made through the other end. The
liquid is unable to rise above the level
of the twisted neck; and this is important,
especially when the aspiration is made
by the mouth. The point is then resealed
at the lamp. The shape of these pipettes
may be varied according to the require-
ments, so long as the same precautions are always
taken to avoid mistakes.

Fig. 102. —Small
pipette with
twisted neck,
corked with cot-
ton wool and
sterilized.

LABOKATOKY RESEAKCH, ETC. 261

Preparations. — Such precautions, and especially
the most scrupulous cleanliness, are necessary in
making preparations, since air, water, dust, the human
hand, and instruments may all introduce foreign
microbes. The instruments should be washed in abso-
lute alcohol, and it is still more effectual to heat them
to a temperature of from 150° to 200°.

As to the liquids (pus, mucus, etc.), the upper sur-
face should not be taken, but that which is nearest to
the tissues, and it should be spread on a thin slide
by a platinum wire, which has been heated red hot
and then allowed to cool.

When the tissues are to be examined, part of them
is detached by a knife which has been heated red hot.
It is placed in Jung's freezing microtome, in order to
cut sections, after it has been hardened in alcohol, to
which bichromate of potassium is sometimes added.
The sections are made as large as possible, and are
then instantly transferred to a capsule full of alcohol,
in which they spontaneously unfold. The glass or
platinum needle, and the nickel or platinum spatula,
serve to spread out and smooth these sections.

Staining Methods. — Aniline dyes have the property
of giving a more vivid colour to the bacteria than to
the surrounding tissues, often even without destroying
them or altering their movements. This property has
been turned to account, and the staining of preparations
is now largely practised.

Methyl-violet, or fuchsin, in aqueous solution, serves

262 MICROBES, FERMENTS, AND MOULDS.

to stain the living bacteria in a drop of water, under
a cover-glass. A small drop of the staining liquid is
slowly diffused into the preparation, and gradually
tinges the bacteria without giving any sensible colour
to the liquid which contains them. When the comma
bacillus of cholera is thus treated, it is still capable of
motion after the lapse of twenty-four hours, and it will
continue to develop if the stage of the microscope is
heated to 25°.

In sections which have been hardened or dried in
alcohol the bacteria have ceased to live, but they may
be stained with the following reagents — Grenadier's
borassic carmine, hematoxylin, and tincture of iodine
may be respectively employed, according to the species
of microbe which is to be stained: Micrococcus, the
flagellum of bacteria, Bacillus amylobacter, moulds,
etc.

Aniline dyes, with an alkaline or acid basis, are
very numerous and varied ; methyl- violet and gentian
in oil of aniline, or in aqueous solution, rosine, saffronine,
Bismarck brown, purpurine, etc.

It is often desired to effect a double staining of the
section, the tissues, for example, being stained red, and
the bacteria violet, or conversely. Picrocarminate of
ammonium gives this effect by the following process : —
After staining the preparation with methyl-violet, it
is dipped for a moment in the iodide solution, and
washed in water or weak alcohol ; it is then steeped
for some minutes in the picrocarminate, of which the

LABOKATOBY RESEARCH, ETC. 263

colour is made lighter by washing with absolute
alcohol and oil of cloves, and the preparation is after-
wards mounted in balsam. The nuclei of the cells are
then of a carmine red, and the bacteria are violet ; the
rest of the preparation is of a much paler colour.

Ehrlich's Method. — We mentioned this method
when speaking of the bacillus of tuberculosis. It
consists in treating the sections or mounted prepara-
tion with a solution of methyl- violet in aniline oil, and
the colour is afterwards quickly discharged in nitric
acid ; the bacteria alone remain violet. Fuchsin,
methylene blue, coccinine, vesuvine, etc., are also em-
ployed in various processes for staining bacteria.

Measurement, Drawings, and Photographs. — Bac-
teria are measured by comparing them with the
divisions of the micro-millimetre slide placed on the
stage of the microscope over the preparation. The
microbes may be drawn without much difficulty by
means of the camera lucida — at least, after a little
practice, as their forms are not at all complex. But
the results afforded by photography are, as it is plain,
very superior. The photographic plate is indeed more
sensitive than the eye, and often allows us to see
details which had escaped the latter. Koch has given
good illustrations of pathogenic bacteria in his book
entitled, Beitrdge zur Biologie der Pflanzen, voL ii.
(1877).

Methods of Microbe Culture. — The development of
microbes may be observed by placing the drop of

264

MICROBES, FERMENTS, AND MOULDS.

.liquid to be examined in Ranvier's moist chamber,
consisting of a glass holder, with a circular groove and
a flat space in the centre. On the top is a cover-glass,

Fig. 103.— Different forms of culture flasks employed by Pasteur (from Duclaux).

which is bordered with paraffin or vaseline, in order to
seal it. The groove contains air and a little liquid.

LABORATORY RESEARCH, ETC.

265

The stage of the microscope is maintained at the
requisite temperature.

In order to make cultures in large quantities, other
kinds of apparatus are in use. The liquid supposed to
contain microbes is introduced into sterilized nutritive
liquids by means of a platinum wire, which has been
heated red hot and then allowed to cool; its end is

IS,

Fig. 104.— Gas stove for the heating and
sterilizing of flasks.

Fig. 105.— Pasteur's
culture tubes.

dipped into the liquid, and then instantly transferred
to the culture, while it is exposed to the heat of a
spirit-lamp. The flask is then sealed with a wad of
cotton wool.

The culture liquids employed by Pasteur are the
extract of beer-yeast, an infusion of hay, boiled and
neutralized urine, and the broth of various kinds of

266 MICROBES, FERMENTS, AND MOULDS.

meat. The flasks are all modifications of the form
indicated in Fig. 76. These flasks are heated in an
iron gas stove (Fig. 104), of which the double case is
heated by gasburners, and it contains a basket of iron
wire as the receptacle of the flasks, tubes, etc., which

Fig. 106.— Stand, bearing culture tubes.

are to be sterilized. The temperature, "regulated by a
thermometer, must rise to from 1 50° to 250°.

Tho nutritive liquid is boiled in a porcelain cru-
cible in the open air, and is introduced by breaking
off the tapered end of the flask ; it is then instantly
plunged into the broth, and drawn by an aspiration
through the opposite tube, after which the tapered
end is resealed at the lamp.

LABORATOKY RESEARCH, ETC. 267

The tubes, which have two reservoirs and two
tapered ends (Figs. 105, 106), are very numerous in
Pasteur's laboratory. They are ranged on a stand in
the way shown in the figure.

It is ascertained that the contents of the tubes are
really sterilized by leaving them for several days in
a stove which is maintained at a temperature of 35°.

In addition to the culture liquids already indi-
cated, many others consist of various solutions of
phosphates of lime and potassium, albuminous solu-
tions, etc.

Solid Nutritive Substances. — In order to isolate the
different species of bacteria, and to obtain pure cul-
tures, solid substances are now preferred : eggs, slices
of potatoes and carrots, but especially gelatine and
gelose — which comes from Japan ready for use, and is
said to be extracted from a marine alga — and the gela-
tinized serum of the blood of oxen. All these sub-
stances are transparent, so that the cultures can be
easily observed in glass tubes. Koch, in his Berlin
laboratory, makes almost exclusive use of solid media,
which are first sterilized by similar precautions.

In order to obtain pure cultures, all kinds of germs
are first allowed to grow ; then a very small amount
of them is taken from the culture medium, and
transferred to the sterilized medium, in which fewer
microbes naturally appear. After several repetitions
of this transplantation, sufficiently pure cultures may
generally be obtained within a short time.

268 MICROBES, FERMENTS, AND MOULDS.

Koch employs a more certain method. He makes
his sowings on glass plates, covered with sterilized
gelatine and kept at a temperature of 30°, by means of
a slender platinum wire which has been made red hot,
then allowed to cool, and charged with a very minute
particle of matter, which is full of bacteria. The
colonies of different microbes isolate themselves, and
may be plainly seen on the glass plate with the aid of
a magnifier. Their variable size and characters often
enable experienced observers to distinguish them by
their aspect alone (Fig. 87, 1, 2). The test-tubes,
containing sterilized gelatine, are then inoculated
with the microbe which it is desired to study (Figs.
82, 105), after taking the usual precautions.

The filters used to sterilize liquids are of Sevres
biscuit-ware heated to 120°, or unglazed pottery.
Such is the Charnberland filter already described.

Cultures for Experiments on Animals. — The pro-
cesses we have just indicated are also necessary in
these experiments. Here likewise all the causes of
error which would arise from the want of cleanliness, or
from the impurity of the culture liquids, must be care-
fully avoided; and it must also be ascertained that
the effect produced on the animal is not due to any
other microbe than that of the experiment, nor to
any irritating and septic substance. The experiment
should be repeated several times by taking some of
the blood of the inoculated animal, and making a pure
culture, which may be used to reproduce the disease
in other animals.

LABORATORY RESEARCH, ETC. 269

Attenuation of Pathogenic Microbes. — Successive
cultures have established, as we have seen, the pos-
sibility of attenuating virus, and transforming it into
vaccine. The processes employed to attain this object
are complex and varied, according to the species of
bacterium with which we have to do.

Thus, for fowl-cholera, Pasteur found that cultures
dating from fifteen days, or from one, two, eight, and
ten months, progressively lost their virulence, and he
believes this attenuation to be due to the action of the
oxygen of the air. So, again, Koch supposes that the
action of the air and the desiccation of the germs
produces, after a time, the natural extinction of the
disease.

Toussiant and Chauveau attenuate the virus of
anthrax, as we have seen, by subjecting it to a tem-
perature of from 42° to 43°. Pasteur and Thuillier have
attenuated the virus of swine fever by passing it
through the system of a rabbit. Pasteur has also
attenuated the virus of rabies, of which the microbe
is still unknown, by passing it successively through
the systems of a rabbit, monkey, etc.

Finally, the same result may be obtained by add-
ing various antiseptic substances to culture liquids,
and thus weakening the virulent action of the
microbe.

Vaccination and Inoculation. — The attenuated
virus or vaccine thus obtained may be used for inocu-
lation in quantities which experience indicates to

270 MICEOBES, FERMENTS, AND MOULDS.

be necessary and sufficient, quantities which vary
according to circumstances. In order to vaccinate
a sheep against anthrax, the animal must be held by
its fore feet in a sitting position, so as to present its
belly to the operator ; the tube of a Pravaz syringe,
containing the injection, is then inserted in the base
of the groin, which is devoid of wool. In cattle the
operation is performed at the root of the tail. It is
performed twice — first with a weak vaccine, and, after
the lapse of a week, with one which is stronger.

Every one is acquainted with the process of vacci-
nating the human subject against small-pox, which
may be done either with lymph from an infant or
from a calf. A lancet or grooved needle is employed,
on which there is a drop of lymph, and five or six
punctures are made on the arms or thighs.

We must not imagine that vaccination can become
an absolute preservative from all diseases. For in-
stance, in erysipelas, pneumonia, and gonorrhoea
a first attack is so far from warding off a second
attack of the same disease, that it creates a favourable
field for relapses. It may, consequently, be assumed
a priori that vaccination in such cases would do more
harm than good (Cornil). It is the same with inter-
mittent fever, tuberculosis, syphilis, etc. ; all diseases
by which the same individual may be attacked several
times, and at varying intervals of time — a clear proof
that the first attack has created no immunity against
subsequent attacks.

LABORATORY RESEARCH, ETC. 271

Immunity. — This term is applied to the property
which the organism may acquire of being safe from
attacks of certain diseases due to microbes, either in
consequence of a former attack, or from a condition
which doubtless arises from absorbing the pathogenic
poison in minute doses, often repeated. Acclimatization
frequently constitutes immunity. Thus, in countries
where malaria, yellow fever, etc., prevail, the inhabi-
tants are less apt to contract the disease than
strangers. Such immunity is not absolute, and may
be lost in course of time. This has been ascertained
in the case of small-pox, so that it is prudent to be
revaccinated every ten or twelve years.

272 MICROBES, FERMENTS, AND MOULDS.

CHAPTER VIII.

POLYMORPHISM OF MICROBES.

MICROBES (bacteria, ferments, and moulds) display,
like all the lower types of the animal and vegetable
kingdoms, considerable polymorphism. It is necessary,
therefore, that we should be on our guard, lest this
phenomenon should be the source of errors and con-
fusions very prejudicial to science, either by describing
as distinct species different forms of the same species,
or by being, on the other hand, led to regard as one
and the same species several which are really distinct,
and which for want of proper precautions, have been
brought together in the same preparation, without the
observer being aware of the fact.

We have indicated in the foregoing chapter the
scrupulous care which is indispensable in laboratories
in order to guard against surprises of this kind.
These precautions are not always sufficient, and ex-
perience shows that a single act of forgetfulness or
distraction on the part of the observer is enough to
spoil the result of a long series of researches. More-

POLYMOKPHISM OF MICROBES. 273

over, these precautions often afford only a negative
result, since some bacteria which have been reproduced
for a long while in the same form in a given medium
of culture, suddenly change their form and habits on
being transferred to another medium.

In order to give an idea of the difficulties which
beset this branch of research, it will be enough to
cite the history of lichens, a history well known to all
cryptogamous botanists. The structure of these lower
plants is at once simple and complex, since we may
regard them as formed by the association, or symbiosis,
as it is technically called, in each lichen of a species
of green alga with a species of colourless fungus of the
Ascomycetes group.

De Bary and the botanists of his school, Schwen-
dener, Bornet, Eeess, Stahl, etc., state that in what
is called a lichen the tissues of an alga and those of
a fungus are intermingled in such a way as to form
the structure which constitutes the lichen. Owing
to this close association, a lichen can live like other
plants, not as a parasite, like fungi : the green parts
of the alga assimilate the carbon contained in the
air in the form of carbonic acid, and thus supply
nutriment to the fungus, which is consequently
regarded as a sort of parasite to the alga. In return,
the fungus supplies its mycelium to the lichen, by
which the latter is enabled to fasten on the surface of
rocks or trees.

This attractive theory was in favour for a con-

274 MICROBES, FERMENTS, AND MOULDS.

siderable time. It is now almost completely abandoned,
and recent researches, made with the view of isolating
the alga and fungus which were supposed to co-exist
in the lichen, tend more and more to show that the
lichen is an independent plant, and not merely an
association of two plants of distinct families, algae and
fungL

Errors of the same kind may occur in the study
of microbes, which, from their minute size, their
unicellular nature, the rapidity of their growth, the
variety of their habitat, and the great resemblance
of their form, are still more difficult to distinguish
than lichens. Of this we will give some examples.

Polymorphism of Leptothrix buccalis. — Robin
(1866-1873), after studying the development of
Leptothrix, stated that this microbe first appears in
the form of a micrococcus ; then of a moving bacterium,
resembling B. termo, B. lineolum, etc., and finally it
forms the long immovable rod (bacillus), which consti-
tutes Leptothrix buccalis. This mode of evolution,
supposed to be usual in the genera Bacillus and
Leptothrix, is probably exact, and, with some reserve
as to the specific identity of the different forms
observed by Robin, modern micrographists are dis-
posed to accept it. But Robin goes further: he
regards the anthrax bacillus as specifically identical
with Leptothrix buccalis. The recent progress of
science no longer permits us to allow this identity.
We have seen that there are, at any rate, two

POLYMORPHISM OF MICROBES. 275

species, quite distinct in their action upon men and
animals.

Polymorphism of Moulds. — The comparatively
early researches of Hallier and others tend to show
that the fungi of moulds display considerable poly-
morphism, so as to completely overthrow the classi-
ication of these cryptogams. These researches have
)een recently resumed by Cocardas, who considers
it proved that all the moulds found in saccharine
iquids which have been allowed to ferment and in
pharmaceutical extracts belong to one and the same
species, which is highly polymorphic, and which he
jerms the Penicillium ferment. Cocardas asserts that

has seen this Penicillium ferment pass through
the following successive stages : — Corpuscular (Micro-
coccus), bacteridian (Bacterium,, Bacillus), zooglairian
'colonies, or zoogloea), submerged hyphse (torula,
chaplets, or chains), fructiferous filaments (endogenous
spores), the whole constituting the algous phase of the
cryptogam which floats on the surface of syrup.

The fungoid phase then begins. The swellings
formed on the surface of the liquid by the endogenous
spores bud ; these buds become elongated, partitioned,
and ramified, constituting the aerial mycelium on
which the aerial fructifications are developed, which
can only form outside the liquid.

These fructifications, although all issuing from the
same mycelium, may present either the form of asper-
gillus, of mucor, or of penicillium, according to the

276 MICROBES, FERMENTS, AND MOULDS.

nature of the spores On the fructiferous hypha. In
other words, the characters which have been hitherto
considered as proper to the three genera, Aspergillus,
Mucor, and Penicillium, themselves types of three
very distinct families, are found either simultaneously,

Fig. 107.— The peniciUium ferment (Cocardas). Aerial fructification in extract of
liquorice : the three forms, Mucor (1), Penicillium (2), AtpergitttU (3), borne by
a single hypha A (x 225 diam.).

or successively, on the same hypha, and are only
varied forms of a highly polymorphic species, the
penicillium ferment (Cocardas).

Fig. 107 represents the three forms of fructifica-

POLYMORPHISM OF MICROBES. 277

tion, as Cocardas states that he has seen them, united
and borne by a single hypha, magnified 225 diameters.

Each form of Penicillium belongs to a special
change in the syrup. In syrup which has become
turbid, the ferment is in the corpuscular or bac-
teridian stage; when the syrup is ropy, it is in the
zooglairian or filamentous stage ; when it has turned
sour, it is in the stage of aquatic fructification ;
finally, when the syrup is mouldy, it is in the stage
of aerial fructification.

Cocardas states that he has observed this really
astonishing polymorphism while making use of the
ordinary precautions for averting gross errors. Not-
withstanding facts of the same kind, which have been
put forward previously, notably by Hallier, but which
are frequently contradicted by more accurate research,
it may be asked whether this is not merely a pheno-
menon of confusion, analogous to that which was
rightly or wrongly supposed to exist in the case of
lichens. Fresh researches, made with greater pre-
cision in sterilized liquids, and accompanied by the
most scrupulous precautions, are necessary before
these facts can be definitively accepted by science.

Polymorphism of Fungi of the Human Skin. — It
is more easy to accept, at any rate in part, the poly-
morphism recently noted by Grawitz in the fungus
of Favus (ringworm), which we have already de-
scribed under the name of Achorion Schoenlenii.

Grawitz asserts that Achorion Schoelenii of ring-

278 MICKOBES, FERMENTS, AND MOULDS.

worm, Trichophyton tonsurans of cirinnate herpes, and
Microsporon furfur of variegated pityriasis, are only
different forms of one and the same parasite, of which
he has made a successful culture on gelatine, repro-
ducing its successive appearances.

Grawitz, however, goes further than many micro-
graphists will consent to follow him. He asserts that
all the fungi of the human skin are only trans-
planted forms, modified by the medium, of O'idium
lactis, the white mould found on milk, bread, paste,
potatoes, etc.

So, again, O'idium albicans, the fungus of thrush,
is, as we have said, specifically identical with Sac-
charomyces mycoderma, or flowers of wine, a ferment
whiqh is developed on the surface of liquids which
are acid and contain little sugar. This must not be
confounded with Mycoderma aceti, a true bacterium,
causing the acid fermentation of wine and beer.

Still more recently, in 1883, Malcolm Morris and
G. C. Henderson have stated that in an artificial
culture of peptonized gelatine at the temperature of
from 15° to 20°, spores of Trichophyton tonsurans were
developed, forming ramified hyphse which were after-
wards covered with fructifications resembling those of
Penicillium.

Injections of Mould-spores into the Blood. — Grawitz
injected spores of Penicillium and Aspergillus into
the vascular system of rabbits, with the view of
demonstrating their transformation into bacteria. He

POLYMORPHISM OF MICROBES. 279

thus obtained the formation of small metastatic
centres in the kidneys, liver, lungs, etc. The spores
sent forth hyphae which were able to produce im-
perfect organs of fructification, but failed to effect
the formation of fresh spores. Gaffky, Koch, and
Leber repeated these experiments, and showed that
the acclimatization of any kind of mould in the
interior of the system was impossible, whatever might
be the more or less serious lesions produced by the
introduction of foreign bodies into the blood of a
warm-blooded animal.

Errors caused in Laboratory Experiments by the
Involuntary Mixture of Different Microbes. — We
should be the more cautious about accepting the real
or apparent polymorphism of certain microbes, since
the most scrupulous precautions do not always suc-
ceed in preventing confusion. Of this Klein gives
the following instances.

While he was studying the microbe of anthrax in
his laboratory at the Brown Institution, one of his
friends was studying canine distemper in an adjoining
room. This friend injected the blood of a dog affected
by distemper into a guinea-pig's veins, and was sur-
prised to see the animal die two days later with all
the symptoms of anthrax, and to discover Bacillus
anthracis in its blood. Yet he had made the injec-
tion with a perfectly new hypodermic syringe ; while
Klein, for his own injections, had made exclusive use
of pipettes drawn to a point in the flame of a lamp.

280 MICROBES, FERMENTS, AND MOULDS.

In this case, it must be assumed that the bacilli and
spores of anthrax had settled on Klein's clothes, had
spread to the table and floor of the second cabinet,
and had passed thence on to the guinea-pig's hair
at the moment of the experiment.

Another operator, who inoculated a guinea-pig
with human tubercles, worked at the same table as
that on which Klein performed his experiments on
anthrax. Two of the guinea-pigs died with Bacillus
anthracis in the blood. Yet the pipettes in use had
always been repointed in the fire, and all the other
instruments had been thoroughly heated before the
inoculation.

In another case, on the contrary, a guinea-pig
inoculated with an attenuated culture of Bacillus
anthracis, of which the effect could not be fatal, was
examined at the end of some weeks, and all its organs
were found to be affected by the bacilli of tuberculosis.
On consulting his notes, Klein found that on the same
day he had performed experiments on tubercular
matter in the same laboratory, but he had always
been careful to use different instruments. The same
phenomenon was produced in a rabbit which died, not
of anthrax, with which he was supposed to have been
inoculated, but of general tuberculosis. The inocu-
lating liquid had clearly been impure.

It is probable that Biichner's experiments on the
bacillus of meat were vitiated by a similar error.
Buchner inoculated mice with this bacillus, and believed

POLYMORPHISM OF MICROBES. 281

that he had produced anthrax. But as he had per-
formed numerous experiments on anthrax in the same
laboratory, it is probable that his cultures of the meat
bacillus were impure, and that he had really inoculated
with B. anthracis. The transformation of the bacillus
of meat into that of anthrax is therefore not yet
proved.

Jequirity Microbe. — This is another instance of an
analogous mistake, owing to which the Jequirity
bacillus has been supposed to be transformed from a
merely septic into a pathogenic microbe. This sub-
stance, recently imported from India, is extracted from
the seeds of Abrus precatorius, one of the leguminous
plants. A few drops of the infusion of these seeds
applied to the eye produce conjunctivitis, which is
artificially excited in order to effect the disappearance
of the granules (trachoma) by which the inner surface
of the eyelids is sometimes affected. In India, the
same liquid is used to kill cattle by a simple puncture,
with the object of skinning them.

When Sattler noticed that an infusion of jequirity
became full of moving bacilli in a few hours, re-
sembling bacillus subtilis of an infusion of hay (Fig.
80), he made cultures of this bacillus, and produced
by their means serious ophthalmia in the eyes of
rabbits. At the same time he ascertained that this
microbe was harmless when floating in the air, and
that its pathogenic properties were only displayed
when it was cultivated in an infusion of jequirity.

282 MICROBES, FERMENTS, AND MOULDS.

In spite of this, Sattler ascribes the pathogenic action
of this substance to the microbe.

Klein repeated his experiments 'with great care,
and was successful in solving the contradictions which
appeared to result from Sattler's researches. He
proved that the bacillus of jequirity, taken by itself,
could no more produce an infectious ophthalmia than
Biichner's meat bacillus could produce anthrax. The
poisonous principle of jequirity is a chemical ferment
(Abrine), analogous to pepsine, and independent of
any microbe, and its assumed bacillus probably does
not differ specifically from Bacillus subtilis.

The transformation of an originally harmless mi-
crobe into a pathogenic microbe is therefore not yet
proved, and all known facts contradict the possibility
of such a transformation.

Septic and Pathogenic Microbes. — Hence we are
led to define, more precisely than before, the terms
septic microbes and pathogenic microbes, which are
in current use in bacteriology.

The term " septic " is applied to the microbes or
bacteria which generally live in decomposing organic
matter and in dead bodies. These microbes, or their
spores, are found in the air, in water, or the soil, in
the mouth and intestinal canal of a healthy man or
animal; but they are developed in greater numbers
when the tissues are dead or in a diseased condition,
and also in pus, in the bronchial secretion of pulmonary
catarrh, on the surface of intestinal ulceration, etc.

POLYMOKPHISM OF MICKOBES. 283

Such axe Bacterium termo and Bacillus subtilis, the
microbes of putrefaction, those of the sweat of feet,
etc., of which we have spoken above ; such, again, is
the bacillus of Buchner's meat infusion, that of Sattler's
jequirity, and finally, Grawitz's Aspergillus, mentioned
in this chapter.

These various microbes, inoculated or injected into
blood, may indeed produce different disorders, which
in some cases always remain local (oedema) ; in others
are limited to metastatic centres encysted in various
organs — the liver, kidneys, lungs, etc. ; or, again, they
may produce a general infection of the blood, as in the
septicemia produced by Davaine when he inoculated
rabbits with the fluid of putrid beef. These rabbits
died within two days, and their blood was found to
be full of Bacterium termo. The same result has been
obtained by Pasteur and Koch, by merely inoculating
guinea-pigs and mice with a little putrid earth or
water, in which the same organism was evidently
present. But in no case a disease with distinct cha-
racters was produced by this means, with special
symptoms, epidemic or contagious, analogous to those
of erysipelas, anthrax, tuberculosis, or cholera. Hence
the name of experimental septicemia, since these
diseases do not exist in nature.

On the other hand, those microbes are termed
pathogenic which always characterize by their
presence a special disease, epidemic or contagious, and
possessing special symptoms and lesions, whether this,

284 MICROBES, FERMENTS, AND MOULDS.

microbe subsists in the blood, the inner part of the
organs, or merely on the surface of the digestive canal.
Such are the microbes of anthrax, of tuberculosis, and
of cholera, natural diseases which are not produced by
the experiments of man. Up to this time a septic
microbe has not been proved to be transformed into a
truly pathogenic microbe, and consequently a com-
pletely new disease, characterized by the development
of this microbe in the body of man or animals, has
not been created.

It must also be remarked — and this peculiarity is
common to both classes of microbes — that certain
bacteria produce very different effects, according to
the animals into whose bodies they are introduced.
Thus guinea-pigs cannot be inoculated with the
experimental septicemia of rabbits and mice ; and
dogs and swine display more or less resistance to the
inoculation of anthrax. Finally, there are cases in
which the attempt to inoculate an animal with a
contagious disease merely produces a septicemia
which must not be confounded with it. This result
will not astonish those who know that some species
of plants, poisonous to man, can be eaten with im-
punity by many animals. But it is well to keep
this fact in mind in laboratories, when the attempt
is made to inoculate animals of various species.

( 285 )

CHAPTER IX.

CONCLUSION. \

THE MICKOBIAN THEORY COMPARED WITH OTHER
THEORIES PUT FORWARD TO * EXPLAIN THE
ORIGIN OF CONTAGIOUS DISEASES.

THE parasitic theory of diseases is far from being
generally adopted by medical men ; at this very time
the theory is actively opposed by medical practitioners
of high standing, who are advocates of the theory of
the innate character of diseases. In their opinion, the
disease is spontaneously developed in the patient, or,
at any rate, under the influence of a contagion of
which the nature is still unknown. They consider that
it is only a secondary complication when microbes are
found in the blood, and that these microbes are not
the cause of the disease, nor even the contagious
element, nor the vehicle of contagion. In a word,
the microbian theory is in their eyes a purely gratuitous
hypothesis.

Admitting with them that the microbian theory is

286 MICROBES, FERMENTS, AND MOULDS.

only an hypothesis, let us compare it with other hypo-
theses which have been proposed to explain the
virulent and contagious nature of certain diseases.
This comparison may throw some light on the question
at issue.

The value of an hypothesis must be estimated by
the number and importance of the facts of which it
affords a clear, precise, and really scientific explanation ;
it must also be estimated by its influence on the
advance of science. We will therefore enumerate the
principal theories which have been proposed to explain
the origin of virulent and contagious diseases, without
the intervention of microbes.

Robin's Theory of Blastema. — Although, as far as
we are aware, Robin has not recently published any-
thing with reference to his opinion of the value of the
microbian theory, some of his pupils have set forth the
theory of blastema as it was stated by their master in
books published from ten to twenty years ago.

In Robin's opinion, no cell is born from another
cell, in the form of a bud, an egg, or a spore. Un-
doubtedly there is no spontaneous generation, at the
expense of elements of exclusively inorganic origin ;
but this generation or genesis occurs every day at the
expense of an organized substance which is living,
but fluid and amorphous, and which has its source
•from other pre-existent cells. This fluid is termed
blastema by Robin. Blastema is the surplus of the
nutritive substance, organized by the cells and exuded

CONCLUSION. 287

from them. New cells may be completely formed at
the expense of this blastema, without having their
source in one cell more than in another. According
to Robin's theory, the pus-corpuscles, which are a new
creation, are produced in this way : they result from
the exudation of a fluid which issues from all the
organs, and are not produced by the enlargement,
reproduction, and budding of pre-existent cells, as it
is stated in other theories, and notably in those of
Schiff and Cohnheim.

When this is established, it follows that all diseases

have their origin in a chemical or physiological

change in the blastema, which at one time produces

normal cells, adapted to replace those which die from

natural decay, and at another engenders diseased cells,

which are dangerous, either owing to their too great

number, as in septicemia, or from their peculiar nature,

as in tubercle and cancer. Here we will quote Robin's

words : " The cause of morbid disturbance arises from

the changes which take place in the quantity and

nature of the immediate constituents of the actual

substance of the tissues and secretions. These changes

make the development of minute spores possible. The

multiplication of microscopic plants is a secondary

phenomenon ; not the scientific cause which actually

determines it. The presence of the vegetable parasite

is a complication which has been mistaken for the

cause " (Histoire naturelle des vegetaux parasites de

I'Twmme, 1853, p. 287).

288 MICROBES, FERMENTS, AND MOULDS.

These words were written more than thirty years
ago, and it may be asked whether the immense pro-
gress which science has made since that date has not
somewhat modified the author's opinions. Jousset
de Bellesme is scarcely entitled to take these words
and paraphrase them as follows: — "The microbe,
where it really exists, is only a secondary phe-
nomenon, and it would not be too much to say that
no fresh element has intervened, either in small-pox,
scarlatina, or tubercular disease ; in such cases there
is only an exaggeration and reproduction of normal
elements, which, influenced by wholly obscure con-
ditions, are evolved in an altogether unusual manner."

The definition given by Jousset de Bellesme is not
that of contagious diseases, but of those which are
combined under the generic name of cancer. If he
means to compare these diseases with cancer, such a
comparison is impossible. It is well known that
cancer is not contagious, and this fact alone places a
gulf between these two kinds of disease. Cancer is
not only not contagious nor is it conveyed by inocula-
tion, but it is only hereditary in about a tithe of
cases. Tuberculosis is, on the other hand, a con-
tagious disease, because it is produced by microbes,
and it may be set down as hereditary in nine cases
out of ten.

Jousset de Bellesme's theory, therefore, explains
nothing, and leaves the question absolutely untouched,
since it throws no light on contagion and virulence,

CONCLUSION. 289

the precise points which it is essential to explain.
But we must return to Robin's theory. When he
states that the microbe is only developed in tissues
which are already changed, Robin is not so far from
the parasitic theory as his pupils represent him to
be. It matters little that the microbe may be only
a complication, a secondary phenomenon, if this
secondary phenomenon dominates the whole disease
and invests it with its dangerous character, its con-
tagious and virulent nature. In the case of a viper's
bite, it is not the bite from the animal's teeth which
is dangerous, but the introduction of the venom
which flows from them ; that is, the secondary
phenomenon. And it is the same with an anatomical
puncture.

Two men in similar circumstances are attacked by
pneumonia; the first will recover with ease because
he is only thirty years old, while the other is almost
certain to die because he is seventy-five, but we should
not therefore say that he died of old age, and that the
pneumonia was only a secondary phenomenon.

Oidium and the phylloxera have attacked the
French vineyards which are exhausted by excessive
cultivation, but it will not therefore be denied that
these are two dangerous diseases ; nor should we say
that they are secondary phenomena. It is therefore
evident that Robin's theory, as it is set forth by
his disciples, who have resuscitated statements made
twenty or thirty years ago, is no longer on a level

290 MICROBES, FERMENTS, AND MOULDS.

with, the present state of science, and is in no case
applicable to virulent and contagious diseases.

Theory of Charlton Bastian, and the English Fol-
lowers of his School. — This theory, held by the most
ardent opponents of the school of Tyndall and Pasteur,
is set forth in the writings of Lewis and Lionel Beale.
It scarcely differs from the one we have just stated.
Lewis thinks it very evident that the presence of
microphyta of the blood is only a secondary pheno-
menon; that the change in the fluids of the body is
effected before the slightest trace of their presence can
be discovered. This is plainly Robin's theory.*

Beale is still more absolute and exclusive.! He
holds that the solid particles of vaccine are not bacteria
nor micrococci, but bioplasts, or formulated elements
which have their source in the living substance of the
cow, and these bioplasts constitute the effective con-
tagion of all virulent diseases. Bioplasts are extremely
minute particles of the living substance of the species
affected by the disease. The contagion is a bioplasma,
and each species of contagious bioplasma manifests its
peculiar specific action, and that only. We must
leave it to others to admire and paraphrase this scien-
tific jargon, which seems intended to take us several
ages back. We must, however, observe that Beale 's
theory is somewhat allied to another, much more
serious and complete, of which we have now to speak.

* Les Microphytes du Sang, 1881.
f The Microscope in Medicine, 1882.

CONCLUSION. 291

B&hamp'a Theory of Microzyma. — According to
this theory, diseases are not due to a fluid blastema
which is changed in disease, but to an organized and
solid blastema, resembling the constituents of the
blood, and consisting of very minute particles of living
matter, which are microzyma. These are the elemen-
tary granules which may be seen under the microscope
in the cells and in all the fluids of the organism.
The mycrozyma, and not the cells in which they are
encysted, are the real agents of all the functions of
the organism. By the secretion of a fluid termed
zymase, or ferment, by which they are constantly
surrounded (both together constituting what is called
protoplasm) ; these microzyma effect the various trans-
formations which have for their final object the nutri-
tion of the organism. Virulent and contagious diseases
are not produced by parasites coming from without,
but by the microzyma themselves, owing to a perver-
sion of their normal functions. In such cases they
secrete a vitiated zymase, and are transformed into
micrococci and bacteria, which it is an error to regard
as foreign bodies, since they are only the result of the
special form of microzyma pre-existing in our tissues.

It must also be said that these microzyma are im-
perishable. The cells of our organism die and are
renewed, but the microzyma which they contain are
only associated with other microzyma in order to
constitute fresh cells. After death, their transforma-
tion into microbes produces putrid fermentation, and

292 MICKOBES, FERMENTS, AND MOULDS.

their existence is prolonged far beyond that of the
organisms of which they temporarily formed part.
Thus the microzyma of chalk, which doubtless have
their source in the animal and vegetable tissues of
that epoch, are still living after a repose of many
thousand centuries, and may be transformed into
bacteria if supplied with the fitting nutritive liquid,
as Bechamp has demonstrated.

This is undoubtedly a very attractive theory,
which would explain a larger number of facts than
the theories previously stated, yet it is impossible to
make it agree with some of these facts, while they
are readily explained by the parasitic theory. Such,
for example, are the phenomenon of putrefaction, and
the benefits of Lister's dressing, and of Guerin's pro-
tective method applied to wounds.

Robin, in his theory of blastema, also stated that
putrefaction took place without the intervention of
any external agent.

It is, however, now known that when dead bodies
are protected from air-germs, they do not putrefy, but
become mummies. Such is the case with the bodies
which have been preserved for many centuries in the
crypt of one of the churches in Bordeaux, and which,
without any antiseptic preparation, have gradually
passed into the state of mummies. Many underground
buildings and caverns, in which the air is dry and
the temperature invariable, present conditions favour-
able to such transformation, doubtless because this

CONCLUSION. 293

situation is unfavourable to the life of the lower
plants.

The theory of microzyma explains the transmission
of diseases by the organized elements of the virus,
while the filtered liquid of the same virus is unin-
jurious, and in this respect it is more in accordance
with facts than the theory of blastema; but it does
not explain the effect of the exclusion or sifting of
the air by Gue'rin's dressing, nor that of carbolic acid
in Lister's dressing. In fact, if the virulent microzyma
are in the patient's body, and have no external source,
it is difiknilt to understand of what use this process
can be. It is evident that the cotton wool, which only
arrests the solid particles of the air, while admitting
the air itself, must act by warding off something
suspended in the air, and the matter in suspension
can only be organized bodies, or air-germs.

Theory of Ptomaines. — Special alkaloids (septine)
were discovered by Panum in pus and by Selmi and
Gautier in putrefying matter (ptomaines), and par-
tizans of the theory of non-organized virus appeal to
these as a last resource. It has been supposed that
these ptomaines or toxic alkaloids were the product
of putrefaction, or morbid changes which were purely
chemical, produced in the tissues and fluids of the
system, without any external intervention of microbes.
This a priori idea does not really differ from Robin's
theory of blastema. If it is accepted, all pathogenic
microbes resemble Sattler's jequirity bacillus, which

294 MICKOBES, FERMENTS, AND MOULDS.

certainly lives and is developed in the toxic juice of
the seeds of Abrus precatorius, but which, as Klein
has shown, has no influence on the artificial conjunc-
tivitis produced by the aid of this liquid.

This theory of ptomaines without microbes is,
however, inconsistent with an impartial study of facts.
It is true that a suitable filtration will separate the
ptomaine from its microbe; but the converse, as in
the case of the jequirity liquid, is impossible. When
this microbe is separated from the original liquid,
and transferred to the infusions of successive cultures,
so as to purify it from every foreign element, it
continues to produce its characteristic ptomaine, which
is manufactured completely at the expense of the
culture liquid, as Pouchet's recent experiments on the
ptomaine of cholera have shown. There is no ptomaine
without its special microbe, any more than there is
ergotine without Claviceps purpurea, or vinegar
without Mycoderma aceti.

Pasteur's Microbian Theory is the only one which
explains all Facts. — The microbian theory is the only
one which is not obliged to have recourse to the vague
expressions with which medicine was formerly content
to explain the contagion of diseases, and which still
satisfies Jousset de Bellesme, when he speaks of the
wholly obscure conditions which accompany the pro-
duction of these diseases. All the expressions of
miasmata, virus, effluvia, etc., which were in use twenty
years ago to designate that unknown agency which

CONCLUSION. 295

constitutes contagion, could only be defined by having
recourse to the term " catalytic action," which merely
placed the solution of the problem another step back,
and substituted one unknown thing for another.* The
parasitic theory will have done much for science if it
only delivers us from "miasmata," "effluvia," and,
above all, " catalytic action." As soon as it had been
shown that miasmata and effluvia, as well as virus, were
only air-germs — that is, microbes and their spores — a
brilliant light was thrown on all pathology, of which
the benefits may be measured by the great work accom-
plished in this direction within the last ten years.

This theory has given us Gue'rin's protective treat-
ment of wounds, Lister's antiseptic dressing, and
Pasteur's new vaccine, and these three great dis-
coveries are enough to render the hypothesis immortal,
even admitting that it is only an hypothesis. The
adverse theories, when opposed to the microbian
theory, can show us no progress effected in science,
and this suffices to condemn them.

Moreover, the microbian theory is no longer in
the primitive stage in which it can be regarded as
a pure hypothesis, since it has entered the domain
of positive facts. Before an infectious disease can be
considered due to the presence of a specific microbe,

* See, for example, the article Miasmes in Nysten's Dictionary
(Littre and Robin, edit. 1864) : " Miasma is constituted by the organic
substances of the air, in different stages of catalytic modification." These
words are printed in italics by Robin himself. See also the words
Efluves, Catalytiques, Virus, etc., in the same dictionary.

296 MICROBES, FERMENTS, AND MOULDS.

it is indispensable to submit it to the test of the four
following rules, which have been clearly established
by Koch : —

1. The microbe in question must have been found
either in the blood or tissues of the man or animal
which has died of the disease.

2. The microbe taken from this medium (the
blood or tissues, whichever it may be), and artificially
cultivated out of the animal's body, must be trans-
ferred from culture to culture for several successive
generations, taking the precautions necessary to
prevent the introduction of any other microbe into
these cultures, so as to obtain the specific microbe,
pure from every kind of matter proceeding from the
body of the animal whence it originally came.

3. The microbe, thus purified by successive cultures,
and reintroduced into the body of a healthy animal
capable of taking the disease, ought to reproduce the
disease in question in that animal with its charac-
teristic symptoms and lesions.

4 Finally, it must be ascertained that the microbe
in question has multiplied in the system of the animal
thus inoculated, and that it exists in greater number
than in the inoculating liquid.

These four conditions are necessary and sufficient,
and in the present state of science they may be
regarded as fulfilled in a considerable number of
diseases : in anthrax, fowl cholera, swine fever,
glanders, small-pox, tuberculosis, erysipelas, and even

CONCLUSION. 297

in Asiatic cholera. These are undoubtedly microbe
diseases in every sense of the term.

The opposition which the microbian theory
encounters in pathology is not new, and need not
surprise us. In all ages medicine has clung to its old
traditions, and has been unwilling to renounce the
habit of regarding disease as something mysterious,
just as in the times of ancient magic, of which our
modern seers and sorcerers are a relic. The parasitic
theory is too simple and natural to be accepted without
a struggle, but its earlier achievements are a good
omen for the future. We need scarcely remind our
readers that at the beginning of this century the
parasitic theory of itch encountered the same opposi-
tion, yet no physician now doubts that Sarcoptes
scabiei is the sole cause of the disease. Somewhat
later, towards the middle of the century, when the
presence of special microphyta was ascertained in
most skin-diseases, the importance of this discovery
was denied; yet few physicians will now dispute
that these microphyta are the chief, or rather the
sole cause of these diseases.

So, again, in anthrax, when we observe the blood
and all the organs filled with bacteridia (Bacillus
anthracis), it can hardly be denied that this disease
is essentially parasitic. Since these bacteridia are
living beings which grow, are reproduced, and breed
with great energy, it must be admitted that their
presence constitutes an immediate danger, especially

298 MICKOBES, FERMENTS, AND MOULDS.

since it is known that they elaborate, at the expense
of the organism, a violent poison (ptomaine), which
penetrates wherever the bacteridia cannot find their
way. It can hardly be said that in this case the
bacteridia are only a " secondary phenomenon ; " that
is, an unimportant complication which gives no cause
for uneasiness.

What we have here said of anthrax also applies
to other diseases : to diphtheria, small-pox, and inter-
mittent fever. We venture to say that if our instru-
ments were not sufficiently powerful to enable us to
see the organisms which cause these diseases, reason
alone would oblige us to admit their existence, from
our general knowledge of the cause and nature of
contagious diseases. The word "contagion" implies
microbe, and the simplicity of the theory gives it
value, and permits us to regard it as the expression
of actual facts.

After this, it is unimportant to know whether the
microbe is itself the contagion, or only its vehicle ; if
it acts by itself, or only by the production of ptomaine ;
if there is a specific microbe for each kind of disease,
or if this microbe is susceptible of transformation, like
other living things, according to the nature of the
medium in which it is nourished. These are secondary
questions, of which the future will doubtless afford the
solution, but which do not affect the principle of the
parasitic theory. That theory is only just established ;
each day brings a fresh stone to the edifice, but we

CONCLUSION. 299

must not yet expect it to be complete in all its parts.
The advance of science may modify its details, but it
may be asserted that the foundation itself will remain,
since it relies on the simple and natural interpretation
of facts.

APPENDIX.

TERMINOLOGY OP MICROBES : VARIATIONS IN DENOMINATION
AND CLASSIFICATION.

IN consequence of the polymorphism of microbes, the
terminology employed by different authors is very unstable.
We have given the established morphological classification
which is still most generally used, but we must here add
some remarks which will make it more easy to understand
the works recently published on microbes, such as lies
Bacteries, by Cornil and Babes, and Micro-organisms and
Diseases, by Klein.

We must first note the tendency to eliminate the names
of two genera : Bacterium and Vibrio.

Cornil and Babes give the name Bacteria, which is the
title of their work, to the whole group of Bacteriacece, or
microbes strictly so called, regarded as a distinct order.
They have consequently been led to suppress the genus
Bacterium, in order to avoid confusion ; and most of the
species formerly assigned to the genus Bacterium are
regarded by them as Bacillus, whether the individual is
long or short, mobile or stationary. In the description
of the microbes of human diseases, we have conformed

302 APPENDIX.

to this nomenclature, which appears to be adopted by
histologists, so as not to overload the synonymy of
microbes, which is already somewhat encumbered. It is
probable, moreover, that this assimilation is correct,
and that most bacilli pass through a phase in which they
are short and mobile, before becoming elongated and
stationary. On the other hand, certain types of the old
genus Bacterium — for instance, the bacteria in the form of
an 8 — should rather be assigned to the genus Micrococcus,
or to the new genus Diplococcus.

With respect to the genus Vibrio, it seems to have
been originally only a somewhat heterogeneous collection,
comprising both the chains and chaplets of micrococci or of
short bacteria, and the strictly unicellular organisms which
might be assigned to the genus Spirillum. Klein, how-
ever, reserves this genus for Vibrio rugula and V. Serpens.

The genus Micrococcus (Hallier) is also termed by
Cohn, Spherobacterium, and these two names are now
given to the only unicellular microbes which are round
or oval, stationary, and consequently devoid of cilium or
flagellum, the organ of propulsion.

These micrococci may be in the form of chains or
chaplets (torula), dumb-bells (Klein), the figure 8 (Diplo-
coccus, Billroth), groups of four, and zoogloese or in masses
of greater numbers.

The genus Bacterium (Microbacterium, Cohn) differs
from the foregoing, as Klein states, chiefly in the oval or
cylindrical form of its cells, and still more by the presence
of a cilium or flagellum at one extremity, which gives a
spontaneous movement. They may thus assume the form
of a sponge-cake and of a dumb-bell when they divide in
two, and may also form short chains or zoogloese. As we
have already said, most of these organisms are assigned

APPENDIX. 303

by Cornil to the genus Bacillus ; at any rate, in the case
of organisms peculiar to human diseases.

The genus Bacillus, according to Klein (Desmobac-
terium, Cohn), includes microbes in the form of more or
less elongated rods, which divide by fission into straight,
curved, or zigzagged chains, formed of elements generally
in contact by their square-cut edges, and which may be
considerably elongated in the form of Leptothrix.

Some of these, when isolated or in short chains, pos-
sess a flagellum at one extremity, and are consequently
mobile — such is the case with Bacillus subtilis and most
of the bacilli of putrefaction — but they lose this organ
of movement on passing into the state of Leptothrix.
Bacillus antliracis is always stationary, and devoid of
flagellum. The fact that there is in this genus a vibratory
cilium, and consequently motion, breaks down the barrier
between the genera Bacterium and Bacillus, and con-
sequently justifies Cornil's view.

The genera Spirillum (Spirobacterium, Cohn,) and
Spirochcete are much more rare, and have not given rise
to the same variations in nomenclature.

We conclude by -reproducing the classification of
Rabenhorst and Fliigge, as it is given by Cornil and
Babes, in order to serve as a convenient scheme for the
pathogenic bacteria in which we are specially interested :

304

APPENDIX.

CLASSIFICATION OF KABENHOKST AND FLUGGE.

Isolated, in chaplets or in zoogloeae

Micrococcus.

In large numbers

Round

and

oval

/Solid colonies

irregular colonies ... ...

Ascococcus.

cells. Forming! .l^"

In small definite

zoogloeae 7

numbers

in th

e ^

and

form of I

regular groups

Sarcina.

\Asinglecircularlayer

Clathrocyslia.

Short, isolated, in a mass or in zoogloeae

Bacterium.

Short, jointed

Bacillus.

/Isolated,
inter-

(^ ( Straight
£ I filaments.

Long, im- ( Slender
perfectly ;
jointed. ( Thick

Leptothrix.
Beggiatoa.

Forming
long

laced, <
or in
bundles.

1 Spiral (Short, rigid
Ulaments- (Long, flexible ...

Spirillum (Vibrio).
Spirochoste.

filaments.

( Streptothrix.

With f

alse ram

ifications

[ Cladothrix.

In zoogloeae

Myconostoc.

B.
APPENDIX TO CHAPTER III. (p. 131).

MICROCOCCUS OF PHOSPHORESCENCE.

The phosphorescence of the sea is due to the presence
of Noctilucce, protozoaria of the group of Flagellata, which
come to the surface in stormy weather. Many other
marine animals present the same phenomenon. The
phosphorescence of rotten fish is due to the presence of
a special micrococcus which forms large circular zoogloeee.
The same micrococcus also appears on putrefied meat
and imparts to it a phosphorescent light.

APPENDIX. 303

C.
APPENDIX TO CHAPTER III. (p. 131).

PLANT-DISEASES CAUSED BY BACTERIA.

The presence of parasitic bacteria lias been recently
pointed out as the cause of diseases in plants. In 1880,
Burril, of Illinois, U.S., has declared the shrivelling of
pears to be due to a bacterium which attacks fruit-trees,
and of which he succeeded in making an artificial culture.
In 1882, the jaundice of hyacinth bulbs was ascribed by
Wakker, of Amsterdam, to the development of a bacterium
between the layers, which may finally destroy the plant.
In August, 1885, Luiz de Andrade Corvo presented a
paper to the Academy of Sciences, in which he asserted
that the vine-disease ascribed to Phylloxera vastatrix is
really due to a bacillus, or rather, according to his de-
scription, to a bacterium, which is always found in the
tubercles of the radicles and in the tissues of the vine
which are affected by this disease, termed by him tuber-
culosis. They are also found in the body of the insect,
which thus becomes simply the agent of contagion.

Neither Wakker in 1882, nor Burril in 1880, was the
first to point out the presence of microbes in the diseased
tissues of plants. As early as the year 1869, Bechamp
noticed the presence of microzyma, that is, bacteria, in the
affected parts of plants (Gomptes rendus de VAcademie des
Sciences, vol. Ixviii. p. 466).

306 APPENDIX.

D.
APPENDIX TO CHAPTER IV. (p. 143).

PTOMAINE OF THE MICROBE OF FOWL CHOLERA.

Duclaux cites the following fact in his book, Ferments
et Maladies : — " If a fowl is inoculated with a few drops
from a culture of fowl cholera, the bird sickens and dies ;
but if the liquid has been filtered before using it, through
plaster or porous china, the disease produced is not fowl
cholera. The bird rolls himself up and falls into a passing
sleep, from which he is roused by the slightest noise.

" After a few hours, his recovery is complete. Thus
there are two kinds of symptoms in fowl cholera, of which
the most apparent is due to a species of narcotic (ptomaine)
secreted by the microbe, but capable of independent action,
and not in general ending fatally."

APPENDIX TO CHAPTER V. (p. 171).

CESSPOOLS. SYSTEM OF CAEEYING EVEEYTHING TO THE
SEWEES.

This system, so long advocated in Paris by Durand-
Claye, implies that the water should pour into the recep-
tacles, so as constantly to flush the drain-pipes. A minimum
of ten litres per diem to each inhabitant is necessary for
this purpose.

The household water and rain-water likewise pass

APPENDIX. 307

into evacuation pipes of the sewer by special syphons, and
help to flash them. This system has been applied to the
Hotel de Ville, to the new Guards' barracks, to a certain
number of primary schools, and to many private houses.
The municipal administration proposes to apply this
system to most of the schools, hospitals, and barracks, of
which the sanitary condition is at present far from satis-
factory. They hope eventually to extend the same system
to all private houses, so as to do away with the cesspools —
a reform already effected in many foreign cities, and
notably in Germany.

APPENDIX TO CHAPTER V. (p. 172),

THE SEWERS OF PARIS AND THE PLAIN OF GENNEVILLIERS.

The water issuing from the main sewer of the city is
partly turned into the Seine, partly into the plain of
Gennevilliers, and used, by a system of irrigation, for fer-
tilizing the soil. There was some fear lest the vegetable
mould might be saturated with fertilizing matter, but the
presence of a special microbe was ascertained, which re-
duces organic matter to its inorganic constituents, and
thus adapts them to be absorbed by plants. Schlcesing
and Muntz, who have studied this microbe, term it the
nitrifying microbe. The same system of sewer-irriga-
tion will shortly be applied to another place in the neigh-
bourhood of Paris, Acheres, near the forest of Saint-
Germain.

308 APPENDIX.

APPENDIX TO CHAPTER Y. (p. 172).

USEFUL MICROBES.

We have said that numerous bacteria exist in the diges-
tive canal of a man in good health. Recent researches by
Duclaux, Richet, and Bourquelot tend to show that these
microbes are not only innoxious, but that they play an
active part in gastric digestion, and especially in the
transmutation of albumins into peptones. Since they are,
in fact, living ferments, the transmutation is retarded, if
these microbes are eliminated. It is therefore probable
that they manufacture pepsin.

Pasteur's experiments also tend to show that microbes
aid the germination of plants. If the microbes contained
in vegetable mould are withdrawn from it, without taking
away any other constituent, germination is retarded, and
effected with difficulty.

APPENDIX TO CHAPTER V. (p. 241.)

PTOMAINES OP FISH.

Salt and smoked fish often produce in those who eat
them violent poisoning, which may even end in death.
Aurep, of Kharkov, has recently studied these causes,
and ascribes them to a ptomaine secreted by a microbe,
or perhaps evolved from the fish itself during life, under
the morbid influence of this microbe.

INDEX.

Abrine, 282

Abrus precatorius, 281

A cants, 51

Acescence in wine, 99

Achorion Jceratophagus, 63

Schcenl&nii, 52, 277

Acidity of wines, 99

Acinetce, 3

Actinospora chartarum, 46

Action by presence, 71

Aerobics, 117, 118

Aeroscope, 160

Agaricus comestibilis, 10, 12

melleus, 41

Agnail, 236
Alkaloids, 238-241
Alopecia, 60

areata, 131

Amertume, 98

Ammoniacal fermentation, 107
Amoebae, 3
Anaerobies, 117, 118
AnguilUdce, 97
Antheridium, 30
Anthracnosis, 38
Anthrax, 132-142
Antiseptic dressing, 242-245
Antiseptics, 253-257
Appert's process, 251
Apyrexia, 185

Ascarides, 248
Ascococcus, 91, 93, 304
Ascomycetes, 13, 20
Ascophora mucedn, 46
Aspergillus, 33, 275, 278

glaucus, 26

Attenuation of pathogenic mi-

crobes, 269
Aubernage, 39

Bacillus, 92, 304

amylobacter, 110

butyricus, 110

Jcomma, 198, 203

of anthrax, 133, 134

of cholera, 197, 198

of foot sweat, 232

of gangrene, 232

of glanders, 149

of leprosy, 228

of malaria, 183

of phthisis, 225

of pneumonia, 230

subtilis, 175

Bacteridia, 93

• , their vegetable nature, 85

Bacterium, 93, 301-304

ceruginosum, 130

bombycis, 152

cyanogenum, 129

x 3

310

INDEX.

Bacterium decnlvans, 131

lineola, 95

porri, 232

prodigiosum, 127

subtilis, 175

ternw, 86, 87, 88

xanthinum, 129

Bnregine, 120
Basides, 12
Basidiomycetes, 14
Bechamp's theory, 291
Beggiatoa, 119, 304

alba, 119

Bitterness of wine, 103
Blastema, theory of, 286
Boil, 236
Boissons, 82
Botrytis bassiana, 50
Bougie Chamberland, 249
Butyric fermentation, 105, 109

Carbuncle, 236
Caries, dental, 177-179

, dry, 63

, of cereals, 17

Carpozyma apiculata, 75
Catallacta, 3
Catalytis, 71
Cattle plague, 146
Cellulose, 9, 10
Choetonium chartarum, 46
Chalk, microbes of, 124
Chamberland filter, 240-248
Chlorococcus, 160
Chlorophyl, 10
Cholera, fowl, 142

, mode of propagation, 207

, microbe of, 195-206

Cilia, vibrating, 88
Cladothrix, 92

dichotoma, 93

Classification of microbes, 91, 301

— of fungi, 13
Clathrocystis, 304
Claviceps purpurea, 20, 21
Coprins, 44

Cordiceps, 47, 49

Corpuscles, vibratile, 151

Cossus, 47

Cow-pox, 211, 214

Croup, microbe of, 215-222

Culture flasks, 162, 264

Culture of microbes, 163, 258-

268
Cyanophycea>, 119

Dematium giganteum, 45

Desmnbacterium, 303

Diastase, 80

Diatomacecr, 3

Diblastic theory, 168

Diphtheria, microbe of, 220

Diplococcus, 302

Disease, white, 33

Diseases, action of microbes in,

237-241, 294
of domestic animals, 132-

155

, human, 156-241

of plants, 305

of potato, 31

of silkworms, 50, 150-155

of the vine, 32-42

of wines, 98 -105

, produced by microbes, 7

Drawings of microbes, 263

Earth-worms, 32, 137

Ehrlich (staining method), 225,

263

Elephantiasis, 228
Entomophthora Planchoni, 49

rimosa, 49

Entomophthorea9, 49
Ergot of maize, 24
of rye, 20, 21

Frgotine, 23
Ergotism, 23
Erisyphe, 27

INDEX.

311

Erisyphe Tuckeri, 27, 33
Erysipelas, microbe of, 232, 233
Eurotium repens, 25
Exanthemata, 209-215

Farcy, HO
Favu's, 5-1
Fermentation, GO-S4

, acetic, 95

, alcoholic, 75

, ammoniacal, 107

, butyric. 110

— , lactic, 106

, of beer, 78

, putrefactive, 112

— , vinous, 74
— , viscous, 104
Ferment, of beer, 79-81

of bread, 84

of fruit, 70

— of wine, 74, 75, 76
Ferments, 6G-72
Fevers, eruptive, 209-215
— , intermittent, 179-187

, jungle, 187

, of horses, 194

, recurrent, 187

— , typhoid, 191-194

, typhus, 191

, yellow, 189, 190

Filter, Chamber-land, 2-10-24S
Flarlicrie, 154, 155
Fh.o-ellata, 3
Flagellum, 88
Wear* ill' ri
Fowl cholern, 1 12
Fue'isin, 2GI
i, 3, 9-65

Gangrene, 232
Germs of the air, 156-165
Glairine, 120
Glanders, 149

Glucose, 67
Goitre, 232
Gonorrhoea, 230
Graisse, 98
Gregariniclce, 3
Guerin'a dressing, 242

Hay, infusion of, 162
Hepialus, 47
Herpes, circinnate, 56
Himantia cellaria, 43
Hymeniura, 12
Hymenomycetes, 15
Hyphae, 10

Immunity, 271
Infusoria, 3
Inoculation, 209

for anthrax, 139

for cholera, 201

for pneumonia, 115

for rabies, 148

Instruments for research, 258

259

Isaria pulveracea, 49
sphingum, 48

.Tequirity, microbe of, 2S1

Kava, 83
Kirschwasser, 83
Koumiss, 83

Laboratory research, 25S -271
Labyrinthultx, 3

312

INDEX.

Lamellae, 12

Leprosy, microbe of, 228

Leptothrix, 92, 304

buccalis, 175

, polymorphism of, 274

Lichens, 273

Liquids, culture, 162, 268

Lister's dressing, 244

Malaria, 179

bacillus, 183

Malt, 80

Marsh fever, 179-187

Measurement of microbes, 263

Merulius destruens, 45

Methods of culture, 263

Methyl-violet, 261

Miasma, 170
, human, 191

Microbes, aerobic and anaerobic,
117

, chromogenic, 126-131

, classification of, 91, 304

— , culture of, 263-269
— , defence against, 242-257
destroyers of building ma-
terials, 123, 124

, in general, 1-8

— of bad bread, 130

of baldness, 131

— of blue milk, 129

of domestic animals, 132-

155

of human diseases, 156-241

of jequirity, 28 L

— of saltpetre, 121

of sulphurous waters, 119,

120

of the air, 156-161

of the mouth, 172-179

of the saliva, 173

of the soil, 166

of urine, 107

of water, 165, 166

, part played by, 6, 7

, pathogenic, 282-284

polymorphism of, 272-284

Microbes, ptomaines of, 237-241,

306

, septic, 282

, strictly so called, 85-90

, their mode of action, 237-

241

, useful, 6, 305

, vegetable nature of, 85-90

Microbian theory, Pasteur's, 294-

299
Micrococcus, 91, 92, 304.

auriantiacus, 129

bombycis, 154

candidus, 129

chlorinus, 129

cyanus, 129

diphthericus, 215

fulvus, 129

of gonorrhoea, 231

of peritonitis, 234

of pneumonia, 229

of scarlatina, 210

of small-pox, 211, 212

prodigiosus, 127

septicus, 234

urea, 107, 108

viclaceus, 129

Microsporece, 58
Microsporidia, 152
Microsporon Audouini, 58

diphtericum, 220

furfur, 56, 57, 278

Microtome, 259

Microzoaria, 4

Microzyma, 4, 291, 305

Mildew, 35, 36

Mixture of different microbes,

279

Molinia, 46
Monera, 3
Montsouris, 159
Morts flats, 154
Motion of microbes, 88
Moulds, of dog's excrement, 27
of leather and fruit, 25, 26

of paper, 46

Mucor caninus, 27

herbarium, 46

wucedo, 28, 46

INDEX.

313

HfucorinecB, 27

Muscardine, 50
Mushroom, edible, 9, 11
Mycoderma aceti, 95

wni, 76, 96

Myconostoc, 304)
ftfyaomycetes, 3

NoctilucoB, 304
Nosema bombyda, 152
.Nbsfoe, 90

CEcidiospores, 16
(Ecidium berberidix, 17

rhamnij 17

O'idium, 33

albiccms, 61, 278

lactis, 27S

Onychomycosis, 63
Oogonium, 30
Oomycetes, 13, 27
Oospores, 27

Ophidomonas sanguined, 128
Ophthalmia, purulent, 231
Orleans process, 96
Oscillaria, 9, 119, 185
Oscillatoria, 119
Orteonvyletis, 236

Palmetto, febrili*, 182

mirifica, 127

Panistophyton ovale, 152
Pebrine, 150-154
Pelade, spurious, 24

— , true, 58, 59
Pellagra, 18, 24
Pelletage, 19

Penicillium, 27, 275, 278
— ferment, 275

racemosum, 47

Peronospora Barcinonce, 202

calotheca, 29, 30

vnfestana, 31, 37

viticola, 35-37

Peyer's glands, 192, 193
Phlegmon, 237
Phoma uvicola, 38
Phosphorescence, 304
Photographs of microbes, 263
Phthisis, 223-228
Phycocromycece, 90
Phylloxera vastatrix, 33
Piper methysticwn, 83
Pipette, 260
Pityriasis capitis, 59, 60

versicolor, 56

Pneumonia, 229

Polymorphism of microbes, 272—

284

Polypus, 232
Pousse, 100
Powdered meats, 252
Preparations, 261
Protista, 3-8
Protococcus, 160

nivalis, 128

Ptomaines, 239, 293
Puccinia coronata, 17, 18

favi, 54

graminis, 15-17

Puerperal peritonitis, 234
Pus-corpuscles, 234, 235
Putrefaction, 112-117
Pyaemia, 235
Pyrochoris apterus, 49

Babies, 147-149
Reagents, non-staining, 261

, staining, 261

Ringworm, 52-54
Robin's theory, 286
Rcesleria hypogea, 40
Rot, 40
Rust, cereal, 14

Saccharomyces albicans, 61
apiculatus, 76

314

INDEX.

Saccharomyces conglomerate, 75

ellipsoideus, 74

exiguus, 75

minor, 84

— mycoderma, 61, 62, 76, 278
Pastorianus, 75

— Reesii, 76

Saprolegnia ferax, 47, 48
Sarcina ventriculi, 94, 95
Scarlatina, 210
Schizomycetes, 8, 86, 91, 158
Schizophyta, 8, 86, 91, 158
Sclerotis, 20

Septic and pathogenic microbes,
282

vibrio, 146

Septicaemia, 234

, experimental, 146

Septine, 238
Sleepiness of fruit, 31
Small-pox, 211, 212
Smut of wheat, 19
Solid nutritive substances, 267
Sphacelium, 20, 21
Sphaceloma ampelium, 38
Spherobacterium, 302
Spirillum, 92, 304

tenue, 114

undulatum, 174

Spirobacterium, 303
Spirochcete, 92, 304
— — buccalis, 173

Obermeieri, 188

plicatilis, 173

Splenic fever, 132-139
Sporangium, 29
Sporendonema muscce, 47
Spores, air charged with, 164

, injected into the blood, 278

Sporisorium rnatdis, 18
Staining methods, 261
Staphylococcus pyogenus, 236
Streptothrix, 204
Forsteri, 232

Sulphurous waters, 119
Sulphur, application of, 34
Sweat, red, 231
Sweating foot, 232
Swine fever, 143
Sycosis, 55
Symbiosis, 273

Vaccination, 211-215, 269

for anthrax, 139

Verdet, 18

Vibrio, 3, 93, 101, 117, 301, 304

rugula, 93, 118, 173, 174

septicus, 146, 147

— serpens, 93, 302
Vinegar, ferment of, 86, 95
Viscous fermentation, 105

Whitlow, 236

Wine, diseases of, 98-105

, ferments of, 74-78

Xerosis, 232

Yeast of beer, 78-82

Zoogalactina imetropha, 127
Zoogloese, 114, 115, 129, 175,

304
Zymase, 291

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